Mystery Substance Identification The Identification of Unlabeled Laboratory Chemicals Found on School Premises

Perhaps the most commonly posed question we encounter is, “I have a container of chemical on my shelf. I do not know what it is. Can you help me?” The following text and suggested procedures are an effort to provide the willing science teacher the means to classify such substances for disposal. No, it is not our intent to identify the material for use. It is our intent to classify the material for disposal. It is likely that your mystery substance was inherited. In order to avoid leaving someone else such a legacy we urge you to be rigorous in your labeling activities. If you wish to postpone the identification process, then assume the chemical is severely hazardous and treat it accordingly. This suggests that you would want to protect the container from fire, being dropped, etc. Turn to the index of your Flinn Scientific Catalog/Reference Manual. Find the section dedicated to Chem- Saf Bags and Saf-Stor Cans. A pictorial presentation takes you through the step-by-step process of “packaging” the substance. Once packaged it is likely the material will be safer while it remains on your premises. We feel it is unnecessary to completely identify the item, an PRELIMINARY EXAMINATION undertaking that will involve both qualitative and quantitative analysis. Our goal is not to salvage but to help the science A lot can be learned about a mystery substance teacher rid himself or herself of this mystery substance. Yes, we just by examining its container. If the container is assume the chemical has no value. Since we do not know what not a commercial container then this step may not the chemical is this “no value” assumption appears reasonable. be significant. We mean the container may be a Should you have been able to identify the chemical you are still flask, beaker, etc., as opposed to a chemical com- faced with possible chemical contamination. Salvage is not the pany’s original container. goal. Identification for disposal—that is our goal. If the container appears to be a commercial con- These procedures will help you segregate the mystery sub- tainer, is any part of the label intact? Clues can be stance into a category or class. Each category or class will have gained from a partial label. Perhaps a catalog num- a disposal procedure. These disposal procedures are listed at ber or a lot number is intact. These clues—catalog number or the back of the Flinn Scientific Catalog/Reference Manual. lot number—may be all that is required for immediate identifi- You will probably not know that a mystery bottle or flask con- cation. Contact Flinn Scientific with this information. We may be tains, for example, 0.15 molar hydrochloric acid (aqueous) when able to be helpful with just those clues. Even if only portions of you complete the identification procedure. You would have iden- an original label remain, valuable clues may be learned which tified the material as a strong acid. You would dispose of a will solve the mystery. strong acid using Flinn Disposal Method #24b. Is the container glass? If yes, is it clear glass or amber glass? You may not plan to dispose of the material. It may be your Amber glass can be an indicator that the substance is light sen- plan to store the material while you examine your disposal sitive. We know that the substance would not be hydrofluoric acid options. You may wish to have a professional and licensed dis- since that acid dissolves glass. posal firm handle the material. You now know the material is a Is the container a heat sealed strong acid and you should label the material accordingly. You glass ampule? Such an ampule may want to accompany the now semi-identified chemical with may be a significant clue since a brief narrative describing how you conducted your investiga- a relatively few substances are tion and the conclusion you reached. A disposal firm would ever packaged in such a con- appreciate this information and may bill you for less. tainer. Examples might be You will take your mystery chemical through a series of tests. bromine or adipoyl chloride. These tests attempt to be systematic. Often you can get clues There are solution concentrates without being completely systematic. Frequently there are neg- packaged in sealed ampules. ative clues. Such negative clues will tell you something about Frequently such concentrates are not hazardous. Ampule-type what the substance is not. packaging is also used to assure product quality or concentra- For this reason—the value of negative clues—we exhort you tion. Such packaging is also used to hold very volatile or air- to completely read through this series of procedures. You will find reactive substances. that a complete reading of the procedures will provide the basis Describe your glass container’s closure or cap. Is it a metal for a more thorough understanding of the process. You will see cap? Is it a plastic cap? How would you describe the condition a bigger picture and not simply be following “recipe-like,” step- of the closure? A badly corroded metal cap may reflect the exter- by-step procedures. You will have a better understanding of nal environment in which the container was stored rather than what will happen next. the contents of the container. Today, metal caps are almost

FLINN SCIENTIFIC, INC. • P.O. Box 219, Batavia, Illinois 60510-0219 • Fax: (630) 879-6962 • 1-800-452-1261 1 never used on glass bottles. A metal cap also use corks or rubber stoppers to close a container. Is the cork may only tell us that the substance is badly discolored or crumbly? Many strong acids or strong bases more than two decades old. Describe will have that effect on cork. To our knowledge rubber stoppers the condition of the plastic cap. Does it were never used by any chemical packager. It is possible that appear to be intact or does it show signs the use of a rubber stopper would provide some clues. Has the of destruction from within? Such cap stopper swelled, lost its shape or is it out of proportion? Many destruction may be the result of contact halogenated organic compounds, and even vinegar (acetic acid) with a very strong oxidizer. will have that effect on rubber. Few inorganic substances will so Perhaps the closure is not a cap at all deteriorate rubber. but is rather a rubber stopper, a cork or Is your mystery chemical container transparent? Is the sub- even some kind of unique closure. Ethyl ether (diethyl ether) is stance solid or liquid? commonly packaged in a metal can with a soft metal hood. The Does the substance appear to be both solid and user must cut away the soft metal hood to open the container. liquid? Can you characterize the substance’s The cap or closure can give meaningless, somewhat mean- color? Is the substance homogeneous or hetero- ingful, or very meaningful clues about the contents of the con- geneous? If the substance is a solid can you char- tainer. Even the cap color may play a role. As you know, common acterize its form, e.g., powder, crystal, granular, acids and ammonium hydroxide are packaged in glass contain- etc.? If a liquid, has it about the same viscosity as ers with color-coded caps. The color codes are as follows: water or would it be more viscous—like honey? Substance Cap Color A colorless liquid or a white powder could be any one of millions of substances. However, a blue, Acetic acid...... Brown granular solid is likely to be one of only a few Ammonium hydroxide ...... Green copper-containing ionic compounds. Hydrochloric acid ...... Blue Such a simple inspection (color, consistency, form, etc.) cou- Nitric acid ...... Red pled with a little chemical knowledge might be just enough infor- Phosphoric acid ...... White mation for the identification process to move along with some Sulfuric acid ...... Yellow speed. Do not accept cap color as a guarantee of the bottle contents. Take a few moments now to review the color table that is There are cases of budget conscious science teachers switch- included as part of these procedures. Almost all of the sub- ing caps on acid bottles. Given enough exposure time, nitric acid stances (dry chemicals, organic and inorganic; solutions; etc.) will slowly destroy the plastic cap. Rather than rid themselves of found in the Flinn Scientific Catalog/Reference Manual are incor- the substance, teachers may use another available cap from an porated into this list. This list represents substances most likely empty bottle. We will have to take our qualitative detective work found in elementary, middle/junior or senior high school science further. We hope you can begin to see the strong reason for departments. reviewing this whole procedure before you start reaching Remember, if the chemical color is clear, white, milky, conclusions. buff or none, and the chemical does not have an odor, it will Any container that appears to have been professionally sealed not appear on this list. likely contains substances that react with air or water vapor in Please note that our list includes information about the liquid the air. Such professional sealing may be a strong enough indi- or solid character of each substance. cator that you should proceed no further but will have to depend The color of every substance listed in the Flinn Scientific on professional assistance. Some examples of materials in Catalog/Reference Manual is provided in the individual product sealed containers might be: listing for that substance. Included also is information about odor. Color can be a very helpful clue in identifying your mystery sub- Bromine Sodium, metal stance. Sometimes color plus a simple confirming test is all that Ethyl ether Sodium peroxide is required for classification. Hydrofluoric acid Adipoyl chloride There are a very small number of chemical substances that Lithium, metal Butyric acid are shock sensitive. An example of such a substance is picric Phosphorus (white/yellow) Pyridine acid. Picric acid is a yellow or yellow/white crystalline material. Potassium, metal Sebacoyl chloride When the substance contains as little as ten percent or more of However, just because a container is not sealed is not a guar- water the material is safe. In its dry state it is a shock-sensitive antee that one of the above substances is not inside. Anything explosive. Please read Flinn disposal suggestion #4a in the is possible! Flinn Scientific Catalog/Reference Manual before proceeding. If The condition of the external surface of your mystery sub- you have any indication or even a suspicion that you are stance container or cap is not a very good indicator of what is dealing with picric acid, proceed no further. You will need inside. The storage conditions surrounding the container (par- professional assistance. That help may have to come from a ticularly if it is metal) may be more responsible for the con- local bomb squad. Picric acid is not likely to be found on school tainer’s condition than its contents. A metal container stored premises—but the possibility always exists. near iodine, for example, may reflect the strong corrosion char- Shock-sensitive chemicals were mentioned at this point in acteristics of a neighboring container. If it is obvious that the sub- our narrative because the next step in the examination process stance is leaking from the container, then that is another matter. is to smell the mystery substance. If you have any reason what- A good example of a substance that appears to have frothed out ever to think you are dealing with a shock-sensitive material of its metal container is sodium peroxide. This substance is fre- you would, of course, never want to handle the container. Yes, quently packaged in a metal can (like a small paint can). Over we realize you have absolutely no way of knowing what you are long storage periods the sodium peroxide will take on water dealing with since the substance is a mystery. You can under- from its environment and form sodium hydroxide. The sodium stand that it is incumbent upon us to call such a circumstance hydroxide will slowly destroy the metal container. In this exam- to your attention. Not to do so would be irresponsible. This alert ple it is the container’s contents that have damaged the container. may also cause you not to want to handle a substance at all. Years ago corks were used as bottle closures. We still see such Our next step involves an attempt to characterize odor. Please containers on school science department shelves. Teachers will note that in addition to color, odor is now also listed in the body

2 FLINN SCIENTIFIC, INC. • P.O. Box 219, Batavia, Illinois 60510-0219 • Fax: (630) 879-6962 • 1-800-452-1261 “Your Safer Source” of the description of each chemical substance found in the Flinn and some might be, but are not limited to, hydrochloric acid, Scientific Catalog/Reference Manual. ammonia, sulfides, bromine and chlorine. Solid, elemental sul- Many chemical reference books make a stab at listing odor. fur is yellow and has a faint odor. Sulfur does not have the rot- Unfortunately, odor is frequently described with words like “char- ten egg odor that characterizes some sulfur compounds. Solid, acteristic odor.” An example might be acetone. If you are famil- elemental iodine usually appears as dark gray flakes with a iar with acetone, perhaps the definition “characteristic odor” is metallic sheen. Iodine’s odor has, sort of, the smell of medicine adequate. If you are unfamiliar with the odor of acetone, we have or a hospital. Iodine emits a vapor that is violet in color. chosen to use more real-life characterizations. In the case of acetone, the Flinn Scientific Catalog/Reference Manual defines Summary of Preliminary Examination its odor as “like nail polish remover.” Throughout the entire chem- • Examine the container for clues. ical listings odor characterizations like: “smells like new leather”; “smells like vanilla” are used instead of meaningless terminology. • What type of container is it? You would, of course, have equipped yourself with the nec- • Does the closure or cap reveal anything? essary safety aids like chemical splash goggles, gloves, an • Describe the condition of the container and its closure. apron, etc. Container opening and small sample removal would • What form is your mystery substance, i.e., solid, liquid? best be done inside your properly operating • Color? fume hood. If a • Odor? hood is not avail- • Is there evidence of air-reactivity? able, then be cer- tain to work in a very well venti- PREPARATION FOR CHEMICAL TESTS lated area. We By this time you should have sensed that our identification pro- are not trying to cedure is a series of steps that is not necessarily systematic. be alarmists, but Rather, we are gathering as much information as possible in our there are many OR attempt to reach a conclusion. Now it is time to do some testing substances that as part of our chemical detective work. can create a Several very helpful tools that every user of chemicals should surprise when have in his/her resource library would be current editions of the opened. A good example might be the com- following publications. If you can only afford one of these publi- mon material, anhydrous aluminum chloride. cations our choice for you would be the chemical dictionary. If the environment is warm and humid, the The Merck index provides more information and detail about a container of anhydrous aluminum chloride substance but the chemical dictionary provides information about may puff and form a cloud of hydrochloric many more substances. acid vapor. Since you have no idea what you are dealing with, you can, we are sure, quickly sense the need for a hood or—at Title Flinn Catalog Number the very least—good ventilation. Chemical Dictionary AP4226 Open your container of mystery substance. Open and close Merck Index AP1361 it very quickly. Remove a very small amount of material. Use a plastic spoon or spatula for dry material or a dropper for CRC Handbook of Chemistry and Physics AP4205 liquids. Place about a 0.1 (1/10th) of a gram or two drops of the Lange’s Handbook AP2093 material on a watch glass. Close the container quickly until this phase of the examination is complete. The Systematic Identification of Organic Compounds by Shriner and Fusion. Obtain this reference from a nearby library. The material removed may surprise you by smoking or ignit- ing on brief exposure to air. Such a reaction is unlikely but pos- Next you will need to accumulate some common laboratory sible. White/yellow phosphorus is an example of such a apparatus and an appropriate place to work. You are again substance. This material is normally in stick form and is stored reminded (if you can) to work under a fume hood or, at the very under water. Other than stick form has been encountered and least, in a very well ventilated lab space. thus our warnings. If you discover the substance is air-reactive, Working alone is not a good practice. Try to have a lab part- stop the examination process. You will need expert advice. ner with you during these investigative sessions. Another science Please call (800/452-1261) or write the Flinn Technical Service teacher would be preferable to asking a student to aid you. Department. If your mystery substance is not air-reactive, then You are again reminded to have all the necessary safety aids please continue. Don’t act quickly. Sometimes very, very old available for your personal use and that of your lab partner. material will be slow to react. Patience is an important safety con- The following lab apparatus should be accumulated for these sideration. Take time to watch before you act. procedures. Most of this material is already probably available We want to check and see if an odor to you. We list the material showing the Flinn catalog number sim- is present. Again open your container and wave your hand over its mouth toward your nose and sniff cautiously. Odor is very much a subjective call but these guidelines may be helpful: Important…For Your Protection! • Most solid substances with strong Read this ENTIRE article on identifying a mystery odors are organic compounds. We substance before you are tempted to start the pro- will discuss this in more detail a lit- cess. Why? Your mystery substance may threaten tle later. your life or health unless handled correctly. Just this • Liquids with strong odors can be organic or inorganic but most once…READ IT ALL BEFORE PROCEEDING! inorganic liquids have little odor. There are certainly exceptions

FLINN SCIENTIFIC, INC. • P.O. Box 219, Batavia, Illinois 60510-0219 • Fax: (630) 879-6962 • 1-800-452-1261 3 ply as a reference and so you can easily identify the item if you material has no metallic look about it at all unless you take a knife are uncertain about what is needed. and cut through this exterior coating to expose the metal. Since old potassium develops peroxides, it is very unwise to cut into APPARATUS such a piece of potassium metal. Peroxides may react with the Description Catalog Number oil or other organic liquid in which the potassium was stored and an explosion may result. If your mystery substance appears to Spatula AP8338 be sticks or chunks of material under oil or kerosene there is a Test Tubes, 100 x 13 mm GP6010 very good possibility that what is present in the container is one Watch Glasses, 65 mm GP8006 of these metals. pH Paper AP1107 Another substance sold in stick form is white/yellow phos- Stirring Rods, plastic AP8150 phorus. Phosphorus would be stored under water, not oil. If the phosphorus has been stored under the same water for an Labels, pressure sensitive, write on AP1293 extended period, it is likely that the water has been converted to Droppers or AP5102 phosphoric acid. This liquid is hazardous. We mention phos- Beral-type Pipets AP1718 phorus at this point only because phosphorus and potassium Burner, micro, gas AP1024 have the single common characteristic of being sold commer- Spoon, metal, micro AP1323 cially in stick form. Do not confuse the two—that could be a ter- Crucible Cover, porcelain AP8247 rible mistake. Old phosphorus (under water) appears to be white Balance: 100 g capacity; 0.1 g sensitivity OB1040 in color. Old potassium (very old potassium) has a yellow, spongy-looking exterior surface. Cylinder, Graduated, 10 mL GP2005 Sodium is also sold in sticks but sometimes it has been sold Cylinder, Graduated, 25 mL GP2010 in large ball bearing size balls. It is also sold as rectangular Plates, glass, cobalt, 3 x 3 AP1058 sticks. Sodium does not develop explosive peroxides, nor does it develop that yellow, spongy look as does potassium. CHEMICALS/SOLUTIONS Lithium has been sold as sticks but is usually sold in wire form. Description Catalog Number We took the time to go into this discussion of sodium, potas- Sodium Hydroxide Solution, 0.1 M, Aqueous S0149 sium and lithium at this point since their forms (sticks, chunks, Calcium Chloride Solution, 0.1 M, Aqueous C0234 wire) do not lend themselves to being extracted from the con- Hydrochloric Acid Solution, 0.01 M H0043 tainer with a spatula or dropper. Here are examples where the Hydrochloric Acid Solution, 0.1 M H0042 physical shape of the substance and the medium in which it is normally stored (oil or kerosene) will deliver a lot of information Potassium Iodide Solution, 1 M, Aqueous Note: The potassium iodide solution must be fresh about the mystery substance. and colorless. If your solution has yellowed it will Prepare Back to the reaction (if any) of our mystery substance with not do for our application here. Do not buy this as needed. water. If a vigorous reaction solution. Make it as needed to be sure it is fresh. Do Not Buy. occurs between your Potassium Iodide Solution, 1 M, Acetic Acid unknown and water, imme- Note: The solvent used to make this solution is diately label the container acetic acid, not water. Make this solution only “Water-Reactive Material.” when needed to assure that it is fresh. Label your container RIGHT Distilled Water W0001 NOW! Fortunately very few sub- EXPOSURE TO WATER stances are water-reactive or air-reactive. 3 mL H O Place about 3 mL of dis- 2 Do not dump your test tilled water in a test tube. tube of water and unknown. Throughout our procedures There is more to be done we will use water. Distilled with this sample. Let the material sit in water for several minutes. water should be used—not Agitate the mixture from time to time using tap water. a stirring rod. Continue to observe the Add 2 drops (if liquid) of mixture until all obvious activity (if any) your unknown. If your ceases. unknown is a solid add The major purpose of our mixing your about 0.1 (1/10th) of a gram of unknown with water was to learn as much the solid to the test tube of water. as we could about water solubility. We Note the reaction (if any). Is the can reach some major conclusions about reaction violent? Does flame appear? Is the reaction heat gen- organic and inorganic materials based on erating? Cautiously touch the exterior of the test tube. Go slowly! water solubility. Take your time. Wait for a reaction (if any). Much more information will follow about The unknown could be one of the alkali metals, calcium car- distinguishing between inorganic and bide, anhydrous aluminum chloride, acetyl chloride or concen- organic substances. At this point, let’s pur- trated sulfuric acid (if liquid). sue water solubility. Let’s talk about water-reactive metals like sodium, potassium If an organic material is soluble in water it is probably an: and lithium. These metals are stored under oil to avoid moisture • Alcohol contact. Sodium and potassium are commonly sold as chunks • Acid or sticks. The sticks of potassium are 3–6 long and about 1⁄2 • Amine in diameter. As potassium ages, it develops a spongy yellow- looking exterior that almost looks like tallow or yellow fat. The or something like one of the above. The substance would, most

4 FLINN SCIENTIFIC, INC. • P.O. Box 219, Batavia, Illinois 60510-0219 • Fax: (630) 879-6962 • 1-800-452-1261 “Your Safer Source” likely, have no more than 5 or 6 carbon atoms in it and, more than unknown is very likely a salt as described above, i.e., a salt likely, it is a liquid. formed from the cation of a weak base combined with the anion If it is inorganic and soluble in water it is very likely to be: of a strong acid. You may get a precipitate on the addition of the sodium hydrox- • A salt with an alkali metal or the ammonium ion as the cation. ide solution. Note the color. Now combine this new knowledge • A salt with the anion being a nitrate, chloride, bromide, iodide with what you learned previously. The combination of informa- or sulfate. tion may help you to more closely identify your unknown. An • A salt having both of the above characteristics. example: A white solid that dissolves in water; has the pH of a If your mystery substance is both soluble and colored, the weak acid; and precipitates with a small quantity of base is likely possibilities become even clearer. to be a salt of aluminum, cadmium, lead or zinc. Refer back now to our color chart. Compare your solution’s If you get no precipitate but an odor of ammonia is obvious, color with the color chart. If you added a colored solid to the you no doubt have an ammonium salt. water, and the resulting color of the solution is very intense, the If the pH of your unknown is between 8 and 11 the unknown material is likely to be a pH indicator, a biological stain or dye, is likely to be: or potassium permanganate. • A weak base We are not through with • A very dilute strong base your test tube yet so don’t pH Indicator Paper • The salt of a weak acid combined with a strong base dump it. Next we want to check the pH of the Care is needed as we proceed here. Even though there are solution. many, many harmless substances which fit into these afore- Place a drop of your mentioned categories you cannot simply add acid to your solution on a strip of pH unknown solution as we added base in our previous tests. An indicator paper. If the pH of your solution is below 3 or above 11 example of a very dangerous material that fits into the third cat- your solution should be considered corrosive. Label your container egory listed above is potassium cyanide. Adding acid to potas- with an appropriate designation like: CORROSIVE LIQUID, ACID, sium cyanide would release the very poisonous gas hydrogen pH = 2 or, if a solid, COR- cyanide, HCN. ROSIVE SOLID, BASE, pH It would be irresponsible and, perhaps, deadly to acidify “just = 13. It is quite likely that a little” to see if you can detect the well-known “bitter almond” your mystery substance is, smell of HCN. Many people are insensitive to this smell. Don’t in fact, a strong acid or a discover your insensitivity by making such a fatal mistake. There strong base or a material is no unambiguous, quick and easy test for cyanide ion. that reacts with water to Another potentially dangerous material in this category is form a strong acid or base. sodium sulfide. You will, most likely, recognize this or other sol- You may dispose of uble sulfides by the characteristic rotten egg odor. This odor materials that test acidic results from small amounts of hydrogen sulfide always present using Flinn suggested disposal procedures #1a, #1b, #24b or with soluble sulfides. Adding acid to any sulfide can release #27c. Materials that test basic would call for use of suggested large quantities of hydrogen sulfide. Hydrogen sulfide is even procedures #3, #10, or #25. more hazardous than hydrogen cyanide. Other identification data gathered during our investigation will If you can eliminate the pos- enable you to more closely identify the substance. Based on that sibility of dealing with cyanide 0.1M CaCl2 additional information you will be better able to choose from the or sulfide in this category you above suggested disposal procedures. are on much safer ground. If your solution tests between 3 pH and 5 pH you most likely Let’s try to do this by adding a have: very dilute (0.1M) calcium chloride to the mystery solu- • A weak acid tion in your test tube. If a white • A highly dilute strong acid precipitate forms, you most • A salt formed from the cation of a weak base combined with likely have a phosphate or car- the anion of a strong acid. bonate as an anion in a salt, not cyanide or sulfide. If your Ordinary tap water will usually have a pH of about 5.6. Many unknown was originally a liquid and smells like ammonia, it is think water has a pH of 7.0. This is usually only true with very probably a solution of ammonia in water or the first of our base pure, freshly distilled, or recently boiled water. Distilled water that categories, i.e., a weak base. has been stored for some time would contain dissolved carbon If you cannot eliminate cyanide as a possibility then you can- dioxide. not proceed further. You need expert help for testing and ulti- Add some dilute (0.1M) 0.1M NaOH mately disposing of soluble substances in this pH range. Please sodium hydroxide to your mys- review Flinn suggested disposal procedure #14 which discusses tery solution. If nothing hap- cyanide disposal. Our warnings may appear to be hyper-cautious pens it is likely to be one of the first two above, i.e., a weak acid or a highly diluted strong acid. These weak or highly Important…For Your Protection! diluted acids can be disposed of using the Flinn suggested Read this ENTIRE article on identifying a mystery disposal procedure #24a or #24b depending on whether the substance before you are tempted to start the pro- material is organic or inorganic. cess. Why? Your mystery substance may threaten In our example of a weak or dilute acid, nothing happened on your life or health unless handled correctly. Just this the addition of 0.1M sodium hydroxide solution. Let’s assume once…READ IT ALL BEFORE PROCEEDING! now that something does happen. If activity occurs, your

FLINN SCIENTIFIC, INC. • P.O. Box 219, Batavia, Illinois 60510-0219 • Fax: (630) 879-6962 • 1-800-452-1261 5 but the risks of not being cau- If the density is greater than 1.00 and the liquid is soluble in tious are great. For those of you water, then the unknown could be concentrated nitric (d = 1.5) who are a little more chemically or sulfuric acid (d = 1.86). curious as well as chemically If the density is greater than 1.00 and the liquid is insoluble in adept, later on a test (more com- water, the unknown is most likely to be a halogenated hydro- plex than any we have dealt with carbon of some kind, e.g., carbon tetrachloride (d = 1.59). so far) will be given for cyanide Now would be the best and first opportunity you might have to and sulfide compounds. use the handbooks you have available as a resource. Refer to If your material is not soluble the tables of organic compounds for density and solubility in your test tube of water, a lot information. of knowledge has also been gained. Is your unknown more or AN OXIDIZING AGENT? less dense than water? Is it a liquid that Some materials found to be oxidizing agents may be unpre- is insoluble and also sinks to the bottom dictably explosive, e.g., organic compounds like ethyl ether and, of your test tube? If yes, the likelihood is that you have an organic as we have learned most recently, even isopropyl alcohol can compound containing at least one halogen atom, e.g., bromine, develop explosive peroxides on aging and long exposure to air. chlorine, fluorine or iodine. The peroxides developed If it is an insoluble liquid floating on top of the water, the in some substances are chances are that it is an organic compound with at least five car- strong oxidizers. We need bon atoms and does not contain a: pH Indicator Paper to perform a test for oxi- • Halogen atom dizing agents before we • Hydroxyl heat any unknowns. • Acid If the unknown was • Amine group found to be water soluble, you should have already This leaves mostly hydrocarbons and fats. determined its pH. Unless If it’s a solid that is insoluble in water, we have not learned a it is already acidic, lower lot except to combine this knowledge with other information you the pH to 5–7 with a small have so far developed about your unknown. quantity of acid. Please Most insoluble solids will be more dense than water. If your 0.01M HCl keep in mind our previous unknown floats, it is most likely an organic substance. exhortations about cyanides and sulfides. This pH adjustment DENSITY can be made by adding very small quantities of dilute (0.01M) hydrochloric acid. Be careful and From the previous work you have already done you have see what small additions of this some idea of the density of your unknown. If the material is a liq- acid will produce in terms of pH uid it is going to be very helpful to get a more accurate measure change. Larger quantities of a of the liquid’s density. stronger acid (0.1M) may be nec- Making density measurements of soluble solids is very difficult essary. Now add a drop of this pH- unless the substance is monolithic. The space adjusted solution to about 1 mL of between particles of granular materials is an aqueous potassium iodide the problem. For insoluble solids, you 1M Kl solution. We earlier alerted you to already know (to a degree) if your make fresh potassium iodide solu- unknown is more or less dense tion that was clear in color. than water. If a yellow or brown color develops, you have a water soluble Using a balance and a gradu- oxidizing agent. This could be a compound with one of the fol- ated cylinder, determine the lowing anions: weight of a measured volume of • hypochlorite the liquid. It is important to mea- • chlorate sure as accurately as you can. • chromate If the density is very close to 1.00 • perchlorate and the unknown dissolves in water, it is • persulfate most likely a dilute aqueous solution of some- • peroxide thing or, alternatively, an: • permanganate • Organic acid • hydrogen peroxide • Low molecular weight amine • organic peroxide • hydro peroxide Pure acetic acid has a density of 1.05. An organic acid or an amine will have a definite odor. An aqueous solution of an It might be best at this point to review the materials with Flinn unknown probably will not have an odor. suggested disposal procedures If the density is less than 1.00 and the material dissolves in #12a, #22a and #22b. water, the unknown is very probably a low molecular weight If your substance is insoluble in alcohol, e.g., ethyl alcohol has a density of 0.79. If the density water, it may be tested for its oxi- is less than 1.00 and the liquid doesn’t dissolve in water, it is prob- dizing power by adding a drop (if a ably a: liquid) or about 0.1 gram (if a solid) to a solution of potassium iodide in • Hydrocarbon (gasoline 0.72; benzene 0.88) acetic acid. Here again we alerted 1M Kl in • Fat (cooking or mineral oil) you earlier to make this solution Acetic Acid • High molecular weight alcohol or amine

6 FLINN SCIENTIFIC, INC. • P.O. Box 219, Batavia, Illinois 60510-0219 • Fax: (630) 879-6962 • 1-800-452-1261 “Your Safer Source” up fresh and on an as-needed basis. The development of a yel- easily may leave a residue. Concentrated aqueous solutions of low or brown color is a positive test for an oxidizing agent. sulfuric acid will leave an oily liquid as a residue. Aqueous solu- In either case, if the material tests tions of gases like hydrogen chloride and ammonia will not leave positive using the potassium iodide a residue. You will probably have already identified these sub- test, label the material NOW as an stances by their acid–base (pH) characteristics or odor. oxidizing agent. If you find that you have a non-burning liquid that leaves a solid See Flinn suggested disposal residue, the odds are high that you have an aqueous solution of procedure #12a for disposal informa- some salt. tion unless it is very clear you have a If you see a strong color in the flame as you are heating a liq- fairly pure peroxide. Refer to Flinn uid (suspected to be aqueous) or a non-burning solid, that can suggested disposal procedure #22a give you a clue as to the identity of the material. What you are or #22b. seeing is the common flame test for many metallic ions. Following is a brief list of the common colors observed in ORGANIC OR INORGANIC? flame tests: Perhaps you have been wondering when we would address Color of Flame Element Indicated this question. It is now time. BLUE Place several drops (if a liquid) or about 0.1 g (if a solid) of your Azure Lead, selenium, CuCl (and other copper compounds unknown on a spoon or a porcelain crucible cover. Bring the 2 when moistened with HCl); CuBr2 appears azure blue, flame of a Bunsen burner up to your small then is followed by green sample VERY SLOWLY! Light blue Arsenic and some of its compounds; seleniun If your sample was a solid does it begin to Greenish-blue CuBr ; arsenic; lead; antimony melt? Will it burn—perhaps like candle wax? 2 Does it give off sparks when it burns? GREEN If a liquid, does it burn or merely boil? Is the Emerald green Copper compounds other than halides (when not flame rather sooty? What color is the flame— moistened with HCl); thallium compounds

yellow, blue, invisible…what? If your liquid Blue-green Phosphates moistened with sulfuric acid; B2O3 boils, does it markedly change the color of Pure green Thallium and tellurium compounds your burner flame? Yellow-green Barium; possibly molybdenum; borates (with H SO ) If your unknown is a liquid, is there a 2 4 Faint green Antimony and ammonium compounds residue remaining after all the liquid boils away? Heat the mate- rial gently, then strongly. This kind of heating (gentle, then strong) Whitish green Zinc can give an indication of the volatility of a substance. RED If your substance is a solid, does it appear to change form or Carmine Lithium compounds (masked by barium or sodium), color as you heat it strongly? Is there a residue remaining after are invisible when viewed through green glass, appear the solid cools? violet through cobalt glass What have we learned from these observations? Scarlet Calcium compounds (masked by barium), appear Most burning is good evidence that you have an organic (car- greenish when viewed through cobalt glass and green bon containing) compound. This is particularly true if your solid through green glass appeared to melt first. Crimson Strontium compounds (masked by barium), appear If you have a fine dust-like solid that burned, it could be a metal violet through cobalt glass, yellowish through green powder. Metal powders will give off sparks when they burn. glass A sooty, yellow flame is a good indication of little or no oxy- VIOLET Potassium compounds other than silicates, phos- gen in the organic compound. An example, please. Gasoline phates, and borates; rubidium and cesium are similar. burns and produces lots of soot. When gasoline is burned in your Color is masked by lithium and/or sodium, appears car engine the carburetor adds lots of oxygen which prevents the purple-red through cobalt glass and bluish-green glass creation of soot. Ethyl alcohol, which contains combined oxygen, burns cleanly with an almost invisible flame. Of the few organic YELLOW Sodium, even the most minute amounts; is invisible when viewed through cobalt glass compounds that don’t burn or at least char when strongly heated, the common ones are the halogenated hydrocarbons (that are A change in form or color when heating a solid that does not mostly water insoluble liquids and are heavier than water). burn gives clues aside from the flame test discussed above. So, the burning test, coupled with the prior tests, should be a Carbonates, upon heating, often give off carbon dioxide, and the very good indicator of whether or not residue will be an oxide. If you have a salt which has water in a the material is organic or inorganic. hydrate structure, heating the salt will often drive off most or all Label anything that burns of the water, and this may lead to a change in color or structure. “Flammable Liquid” or “Flammable Heating pink cobalt chloride hydrate will turn it blue. Heating blue Solid.” Label the material NOW! copper sulfate will turn it white. Do you wish to dispose of these materials yourself? If yes, review Flinn suggested disposal procedures #18a or #18b. Please note that these two proce- Important…For Your Protection! dures, i.e., #18a and #18b are quite similar to Flinn suggested Read this ENTIRE article on identifying a mystery disposal numbers 2, 4b, 4c, 5, 9, 13, 15, 20 and 27j. Burning or substance before you are tempted to start the pro- simple evaporation is appropriate for small quantities of a large cess. Why? Your mystery substance may threaten variety of organic compounds. your life or health unless handled correctly. Just this Certainly water and solutions that are mostly water don’t burn. once…READ IT ALL BEFORE PROCEEDING! Such substances will boil away easily. Solutions that boil away

FLINN SCIENTIFIC, INC. • P.O. Box 219, Batavia, Illinois 60510-0219 • Fax: (630) 879-6962 • 1-800-452-1261 7 Up to this point we have described several simple chemical and Insolubility in: physical tests: • Water • Exposure to air • Sodium hydroxide solution • Visual examination • Sodium bicarbonate solution • Water exposure • Hydrochloric acid solution • pH test But solubility in ether and concentrated sulfuric acid suggests • Density the substance may be: • Oxidizing power • Heating • An ether • Alcohol If you have the facilities, the equipment and a fair degree of • Ketone (of moderate to high molecular weight) organization the whole process may take less than an hour. • A compound having double or triple bonds You may not need to know more than these tests have told you. In many cases you may have been able to learn enough to fol- If a substance is insoluble in any of these aforementioned sol- low one of the Flinn suggested disposal procedures or to pro- vents you will get some information about your substance’s den- vide a professional disposal firm with the results of your work sity if it has not already been determined. which will enable them to classify the substance for disposal. Next, take your copper wire loop and pick Professional disposal firms frequently charge much less for a up a small quantity of your unknown. Place substance which has been generally classified—as opposed to the copper loop with its unknown directly in a complete unknown. the flame of your burner. Halogenated com- pounds (those containing bromine, chlorine FURTHER TESTING or iodine) will impart a very distinct green color to the flame. You have gained a lot of information about your unknown sub- Compounds containing double bonds and stance. It is likely that you now know if the material is organic or aldehyde groups will decolorize very dilute, inorganic. Further testing will build on the valuable information aqueous potassium permanganate solution. you have already developed. Acid halides will give a white precipitate with a dilute, alcoholic Organic? If it is organic you probably do not need to know more solution of silver nitrate. You really must, at this point, spend about it for disposal. Either burn it or evaporate it according to some time with your copy of Shriner and Fuson’s The Systematic the suggested Flinn disposal techniques with which you have Identification of Organic Compounds since the possible permu- become familiar and that were previously listed in this narrative. tations are extensive. Perhaps you are interested in finding out more about your unknown compound. There are several fairly easy tests you can INORGANIC? do. An additional reference book you should have is The Systematic Identification of Organic Compounds by Shriner and Further inorganic identification for safe disposal of your Fuson. Any edition of this reference book will be satisfactory. unknown is directed at creating information as to whether your Among the simple tests you can do are solubility and flame unknown contains: tests. These are not exhaustive, but rather, are intended to be • Cyanide illustrative of the kind of testing and thinking needed for further • Sulfide identification. • Toxic heavy metals More materials will be needed as follows: • Reducing agents • Ethyl ether (diethyl ether) less than 100 mL Cyanide, sulfide and toxic heavy metals are all very danger- • A length of copper wire (approximately 6 long) bent at one ous materials even in very small quantities and low concentra- end to form a small loop. The opposite end will be held by tions. If you even remotely suspect that you might be dealing with a pair of pliers or other appliance used to hold a hot copper such materials, all appropriate and responsible safety steps wire. must be taken. • 0.5 molar aqueous hydrochloric acid solution Water soluble cyanides and sulfides are more dangerous than • 1.0 molar aqueous sodium bicarbonate solution those which are insoluble in water. Many cyanides and sulfides • 1.0 molar aqueous sodium hydroxide solution that are insoluble in water are, in fact, soluble in acid. The pro- • Small quantity of concentrated 18 molar sulfuric acid cess of placing such materials into solution in acids releases very • Bunsen burner dangerous hydrogen cyanide or equally dangerous hydrogen sul- Test the solubility of your unknown in fide. Both are very, very poisonous gases. each of the five solvents listed above. This Does your unknown contain cyanide? might be a fine time to consider perform- We do not recommend trying to prove a water insoluble sub- ing these solubility tests in micro reaction stance contains cyanide. The test involves generating and trap- plates using Beral-type pipets. You already ping a potentially dangerous quantity of hydrogen cyanide gas. have information about your substance However, to test a water soluble substance for cyanide is insofar as water solubility is concerned. much less hazardous; it is known If your substance is insoluble in water but as the Prussian Blue test. The soluble in ether and aqueous sodium hydroxide solution, it is very name, Prussian Blue, comes from likely that your unknown is: the insoluble blue artist’s pigment and is chemically known as ferric • An organic acid of moderate to high molecular weight ferrocyanide. • A phenol To perform the Prussian Blue An acid will be soluble in aqueous sodium bicarbonate solu- procedure: H2O tion while a phenol will not be soluble. • Dissolve a very small amount of the water soluble material in about 10 mL of water.

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• Adjust the pH of this The procedure is as follows: solution to 12–13 pH pH Indicator Paper • If the sample is water solu- using 1 molar, aqueous Lead Acetate ble, dissolve about 0.5 sodium hydroxide solu- Indicator Paper grams in 10 mL of water in tion. As long as your a test tube. solution is strongly • Place a piece of moist lead acetate indica- basic, hydrogen cyanide tor paper just above the solution and allow gas can’t be released. it to adhere to the inside wall of the test tube.

1M FeSO4 • Slowly add, dropwise, 6 molar hydrochloric acid 1M NaOH Litmus Paper to your sample solution until the solution is acidic • Add approximately 1 mL of 1 molar, aqueous to litmus or about pH 5. ferrous sulfate solution which will cause an orange/brown precipitate of iron hydroxide to form. • Boil this mixture for about 30 sec- onds above a Bunsen burner. • Now add 6 molar sulfuric acid drop- wise to the mixture while stirring. The goal is to just dissolve the iron hydroxide with the acid. 6M HCl

6M H2SO4 • Heat the acidified solution. Note any darken- ing of the lead acetate test paper caused by the possible formation of black lead sulfide. This preceding test, if positive, confirms that you have a water soluble sulfide. As the iron hydroxide dissolves, a blue sus- If your unknown is water insoluble then proceed as follows: pension or precipitate remains. It is the pres- ence of this blue material that confirms that • Suspend about 0.5 grams your unknown substance contains cyanide. in 10 mL of a 6 molar hydro- If your test confirms the presence of chloric acid solution. Locate cyanide, label your unknown “solid cyanide the moistened lead acetate Lead Acetate mixture” or “aqueous cyanide mixture” at once. Don’t delay! test paper just above the Indicator Paper Label it now. You would also be wise solution level on the inside to package the material using a plas- wall of the test tube. tic bag and can as depicted in this cat- alog/reference manual under product listings for Chem-Saf bags and Saf- Stor cans. Please review Flinn suggested dis- posal procedure #14. This procedure • Boil the mixture gently over your Bunsen involves oxidizing the cyanide ion to burner. carbon dioxide and nitrogen using calcium hypochlorite solution. • Darkening of the lead acetate paper indicates Heed all of the hazard alerts and other exhortations that are a your unknown contains a water insoluble part of this suggested procedure. In our opinion cyanide disposal sulfide. should only be handled by profes- sionals experienced and equipped to deal with such substances. Does it contain If you get a positive test, immedi- sulfide? ately label the unknown substance This test should only “solid metal sulfide mixture” if it is a be done on a sample solid. which tests nega- tive for cyanide ion. If a substance tests positive for Important…For Your Protection! cyanide, it should be disposed of as a cyanide without any further testing for other ions. Read this ENTIRE article on identifying a mystery This test will release small amounts of poi- substance before you are tempted to start the pro- sonous hydrogen sulfide gas. The amount released is judged to cess. Why? Your mystery substance may threaten be small and inconsequential if the testing is done under a reli- your life or health unless handled correctly. Just this able, operating fume hood using only very small amounts of once…READ IT ALL BEFORE PROCEEDING! sample (about 1⁄2 gram).

FLINN SCIENTIFIC, INC. • P.O. Box 219, Batavia, Illinois 60510-0219 • Fax: (630) 879-6962 • 1-800-452-1261 9 If your unknown is a liquid (most Is your unknown a reducing agent? likely an aqueous solution), make it Most reducing agents don’t carry the same hazard alerts as basic to a pH of at least 12 with 1 do oxidizers. You may have an unknown that has not tested pos- molar sodium hydroxide, aqueous itive to any of our tests. Perhaps it is a reducing agent. Here is solution. Label this mixture “Basic a simple confirm- Sulfide Ion Mixture.” ing test: Does your unknown contain toxic, • Make a very heavy metal ions? dilute solution Justifiable concern is focused on of potassium appropriate and responsible disposal of substances containing permanganate heavy metals. The consequences of irresponsible acts involving by dissolving mercury are well publicized. A good deal is also known about enough in lead but many less well publicized heavy metals present equally water to give a serious problems. A few local governments are now even pro- medium pink- hibiting the introduction of copper ions into wastewater. purple color. Our concern extends beyond the well-being of you and your Such a solution students and includes the environment. Heavy metals must be will be about disposed of responsibly. 0.0001 molar, Materials testing positive for either cyanide or sulfide should but in this case KMnO4 H2O not be tested for heavy metals. accuracy is not Almost all materials in the general category of heavy metals critical. will form insoluble sulfide compounds. Since this generalization is true we can use this test for heavy metals: • Dissolve about 0.5 grams of • Make a solution, if necessary, of your unknown in 10 mL of water. 0.5 grams of your unknown (but If solution does not occur, place suspected) reducing agent in 0.5 g of your unknown in about about 10 mL of water in a test 10 mL of 6 molar hydrochloric tube. H O 2 acid and boil it for several H2O minutes. KMnO4 Solution • Cool if necessary, and adjust pH of the solu- pH Indicator Paper • Add, dropwise, just a few drops tion to 7.0. Use 1 molar of your previously prepared, sodium hydroxide solu- weak, potassium perman- tion and pH indicator ganate solution to your paper to determine the unknown. pH. • Decolorization of the pink- Unknown 0.1M • Add, dropwise, a very small colored solution confirms that KMnO Solution quantity of a 0.1 molar sodium 4 Na2S your unknown is a reducing sulfide solution. This will most agent. likely raise the pH, so readjust the pH to 7.0 using a 1 molar Label your unknown (as appropri- hydrochloric acid solution. The ate) to show that you have deter- 7.0 pH is important since some mined it to be either a “solid reducing sulfides will dissolve in acid and agent,” or an “aqueous reducing others will dissolve in base. This agent.” Please review our suggested disposal procedure #12b. 0.1M 1M is true if excess sodium sulfide HCl Na2S is present. Neutral pH 7.0—is important. CONCLUSION • Any precipitate that forms, usually dark colored, indicates the We could not be exhaustive in our presence of heavy metal ions. Cadmium sulfide forms a bright description of identifying unknown yellow precipitate. substances on your school premises. A very wide spectrum of Label your unknown either “solid broadly applicable tests should help significantly in labeling and heavy metal mixture” or “aqueous properly disposing of your unknown substance. heavy metal mixture” as appropriate. You should not assume that a substance that tests negative In our experience this is acceptable on all these tests is totally harmless and can be placed down the for disposal purposes. drain. You may, after all your effort, still require professional If you wish to consider disposal assistance. yourself, please review Flinn sug- No testing scheme can serve all purposes, nor can it solve all gested procedures #27f and #27h. problems. If you wish to more closely identify your unknown, we would There is no substitute for informed judgment. If you feel you suggest a good qualitative analysis test. One such fine publica- do not have enough information to make an informed judgment, tion is Sorum’s Introduction to Semimicro Qualitative Analysis. then asking for more help is the next logical step. There are several editions of this text, any of which will serve you well.

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CHEMICAL COLOR /ODOR IDENTIFICATION CHART

SUBSTANCE Physical State Odor SUBSTANCE Physical State Odor BLUE GREEN—continued BARFOED’S REAGENT L None FAST GREEN SOLUTION L Slight Vinegar BENEDICT’S QUALITATIVE L None FERROUS AMMONIUM SULFATE S None SOLUTION FERROUS CHLORIDE S Slight Chlorine BIURET SOLUTION L None FERROUS SULFATE S None BIURET, TEST STRIPS S None FUCHSIN ACID S None BIURET SOLUTION L None FUCHSIN, BASIC S None BRILLIANT CRESYL BLUE L None FUCHSIN, NEW S None BROMTHYMOL BLUE L None JANUS GREEN B S None CRYSTAL VIOLET L Alcohol MALACHITE GREEN OXALATE S None CUPRIC ACETATE S None MALACHITE GREEN S/L None CUPRIC CARBONATE S None METHYL VIOLET 2B S/L None CUPRIC CHLORIDE S None METHYL VIOLET 6B S None CUPRIC CHLORIDE L None METHYLENE BLUE S None CUPRIC NITRATE S Slight Nitric Acid NICKEL(OUS) CHLORIDE S/L None CUPRIC NITRATE L None NICKEL(OUS) SULFATE S/L None CUPRIC SULFATE S/L None 4-NITROACETANILIDE S None CUPRIC SULFATE L None RHODAMINE B S None STOCK SOLUTION TOLUIDINE BLUE O S None CUPRIC SULFATE L None UNIVERSAL INDICATOR L Slight Alcohol DITHIZONE S None URANYL NITRATE S None DRIERITE S None GREEN VEGETABLE DYE L None FEHLINGS SOLUTION A L None WRIGHT’S STAIN S None LITMUS S Decaying Plant LITMUS SOLUTION L Cabbage-like PINK TO RED, RUST, BURGUNDY METHYL GREEN L Alcohol ACETO-ORCEIN SOLUTION L Vinegar METHYLENE BLUE L None ALIZARIN S None NICKEL(OUS) AMMONIUM S None SULFATE ALIZARIN RED S S/L None NICKEL(OUS) NITRATE S/L None AURIN TRI CARBOXYLIC ACID S None SILICA GEL S None BISMARK BROWN Y S None THYMOL BLUE L None CALAMINE LOTION L None TOLUIDINE BLUE L None CARMINE S None BLUE VEGETABLE DYE L None CARMINE-ACETO SOLUTION L Strong Vinegar WRIGHT’S STAIN L Alcohol CHROMIUM TRIOXIDE S None COBALT(OUS) CHLORIDE S/L None GREEN COBALT(OUS) NITRATE L None AITCH-TU-ESS CARTRIDGES EMB AGAR S Malt Like (H2S) S None EOSIN Y S None BRILLIANT CRESYL BLUE S None EOSIN Y L None BRILLIANT GREEN S/L None ERYTHROSIN S None BROMCRESOL GREEN L None FAST GREEN FCF S None BROMPHENOL BLUE S None FERRIC OXIDE S None CHLOROPHENOL RED S Burnt Wood FLUORESCEIN S None CHROMIUM (IC) CHLORIDE S None FUCHSIN ACID L None CHROMIUM OXIDE S None FUCHSIN, BASIC L None CHROMIUM (IC) SULFATE S/L None FUCHSIN, NEW L None CRYSTAL VIOLET S None HEXAMETHYLENE-DIAMINE/ L None CUPROUS CHLORIDE S None SODIUM HYDROXIDE SOLUTION 2,6-DICHLOROINDO-PHENOL S Throat Lozenge HYDRIODIC ACID L Slight Rotten Eggs SODIUM SALT INDOLE-3-ACETIC ACID S None

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SUBSTANCE Physical State Odor SUBSTANCE Physical State Odor PINK TO RED, RUST, BURGUNDY—continued YELLOW/MUSTARD—continued 3-INDOLEBUTYRIC ACID S None AMMONIUM SULFIDE L Rotten Eggs IODINE (IODINE-IODIDE) L Iodine BEESWAX S None SOLUTION BILE SALTS S/L Putrid Beef LEAD OXIDE, TETRA S None BRASS S None MANGANOUS CHLORIDE S/L None CARNAUBA WAX S None MANGANOUS SULFATE S None CEDARWOOD OIL L None MERCURIC IODIDE S None CLAYTON YELLOW S/L None METHYL ORANGE L None FERRIC AMMONIUM CITRATE S None METHYL RED L Alcohol FERRIC CHLORIDE S Slight Chlorine 4-(p-NITROPHENYLAZO) S None GLYCERIN, JELLY L None RESORCINOL LANOLIN S Shoe Polish PHENOL RED S None LEAD OXIDE, MONO S None 1,4-PHENYLENEDIAMINE S None LEMON JUICE L Lemon PHOSPHORUS, RED S None LUMINOL S None RED VEGETABLE DYE L None LYCOPODIUM S Fresh-Cut Wood ROSE BENGAL S None MERCUROUS NITRATE S/L Faint Nitric Acid SAFRANIN O S None 1-NAPHTHOL S Slight Phenol SAFRANIN STAIN L None OLIVE OIL L None SAFRANIN L Alcohol PEPTONE S Sour Malt SODIUM NITROFERRICYANIDE S None PETROLATUM S None SUDAN III S None PHOSPHOMOLYBDIC ACID S Inorganic Acid-like SUDAN III L Alcohol POTASSIUM CHROMATE S/L None SUDAN IV L Alcohol POTASSIUM FERRICYANIDE L None POTASSIUM NITRATE S/L None PURPLE/ VIOLET RIBOFLAVIN S None ANILINE BLUE S/L None SOAP S Soap BROMPHENOL BLUE L None SODIUM BISMUTHATE S None CARBOL FUCHSIN L Strong Phenol SODIUM CHROMATE S/L None CHLOROPHENOL RED L None SODIUM COBALTINITRITE S Medicine-like CHROMIUM (IC) POTASSIUM S None SODIUM NITRITE S/L None SULFATE SODIUM PEROXIDE S None COBALT CARBONATE S None SPERMACETI S Wax m-CRESOL PURPLE L None SULFUR S Faint Rotten Eggs CUPROUS OXIDE S None TANNIC ACID S Slight Cucumber FERRIC AMMONIUM SULFATE S None TETRACYCLINE S None FERRIC NITRATE S Slight Nitric Acid HYDROCHLORIDE INDIGO CARMINE S None YELLOW VEGETABLE DYE L None METHYL VIOLET 6B L None YEAST EXTRACT S Sour Malt MUREXIDE S Slight Nitric Acid ZEOLITE S None 4-(p-NITROPHENYLAZO) L None ZINC SULFIDE S None RESORCINOL SOLUTION POTASSIUM PERMANGANATE L None ORANGE TO BROWN, AMBER RHODAMINE B L None ACRIDINE ORANGE L None ALIZARIN YELLOW R S None YELLOW/MUSTARD AMMONIUM DICHROMATE S None ALBUMIN S Slightly Musty BISMARK BROWN Y L None ALUMINUM CHLORIDE S Strong Hydrochloric Acid BOUILLON, CUBES S Beef Broth AMMONIUM CHROMATE S None BROMINE (AMPULE) S Irritating, Chlorine-like AMMONIUM METAVANADATE S None BROMINE WATER L Like Bromine

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CHEMICAL COLOR /ODOR IDENTIFICATION CHART

SUBSTANCE Physical State Odor SUBSTANCE Physical State Odor ORANGE TO BROWN, AMBER—continued BLACK, BROWN/BLACK BROMCRESOL GREEN S None ACRIDINE ORANGE S None BROMCRESOL PURPLE L None BEEF EXTRACT S Putrid Beef BROMTHYMOL BLUE S None BROMCRESOL PURPLE S None CERIUM (IV) S Slight Nitric Acid CATALASE S None AMMONIUM NITRATE CHARCOAL S None CLOVE OIL S Clove CHLOROPHYLLIN S None COBALT(OUS) NITRATE S None COBALT(IC) OXIDE S None COBALT(OUS) SULFATE S/L None CONGO RED S None CONGO RED L None m-CRESOL PURPLE S None COPPER S None CRESOL RED S Burnt Wood CORN OIL L None CUPRIC BROMIDE S Bromine-like COTTONSEED OIL L None CUPRIC CHLORIDE S Slight Vanilla CRESOL RED INDICATOR L None ERIOCHROME BLACK T S New Rubber EOSIN Y L Alcohol FERRIC CITRATE S None FERRIC CHLORIDE L None FERRIC(OUS) OXIDE S None FERRIC NITRATE L None INK, BLACK L None HYDROBROMIC ACID L Suffocating; INVERTASE S Dry Dog Food Bromine-like IODINE S Unique, Acrid IODINE—POTASSIUM L Iodine (Slight) IODIDE SOLUTION IODINE, TINCTURE L Iodine and Alcohol IODINE SOLUTION, GRAM L Iodine NIGROSIN S/L None ION EXCHANGE RESIN S None THIONIN S/L Slight Vinegar LEAD DIOXIDE S None THYMOL BLUE S None LICORICE S Licorice Candy LINSEED OIL L Oil SILVER/GRAY LYSOL S Phenol ALUMINUM S None MERCURIC OXIDE S None ANTIMONY S None METHYL ORANGE S Laundry Soap ANTIMONY TRICHLORIDE S Slight Chlorine METHYL RED S None BARIUM CARBONATE S None MOLASSES L Brown Sugar BARIUM PEROXIDE S None NICOTINE S Strong; Old, BENZOYL PEROXIDE S Faint Almond Smoked Cigarettes BISMUTH S None NINHYDRIN SOLUTION L Butyl Alcohol BOILING STONES S None ORANGE G S None CADMIUM S None ORANGE IV S/L None CALCIUM S None PEANUT OIL L None CALCIUM CARBIDE S Slight Acetylene POLYURETHANE LIQUID “A” L Rubber-like CALCIUM FLUORIDE S None POLYURETHANE LIQUID “B” L None CALCIUM HYDROXIDE S None POTASSIUM DICHROMATE S/L None CARBORUNDUM S None POTASSIUM FERRICYANIDE S None CHROMIUM S None POTASSIUM TRIIODIDE L Iodine-like CHROMIUM(IC) NITRATE S/L None SESAME OIL L None COBALT S None SODIUM DICHROMATE S/L None CUPRIC OXIDE S None SUCROSE S Slight Malt p-DIMETHYLAMINO S Shoe Polish (BROWN CANE SUGAR) BENZALDEHYDE SUDAN IV S None FERROUS SULFIDE S None VINEGAR (CIDER) L Acetic Acid GRAPHITE POWDER S None XANTHOPHYLL S Shellac HYDROQUINONE S None YEAST (BREWERS) S Malt IRON S None IRON PYRITES S None

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SUBSTANCE Physical State Odor SUBSTANCE Physical State Odor SILVER/GRAY—continued *CLEAR, WHITE, MILKY, BUFF, NONE—continued LEAD S None ACETYLCHOLINE BROMIDE S Strong Acetic Acid LEAD SULFIDE S None (Vinegar) LITHIUM S None ACETYLCHOLINE L Slight Vinegar Odor BROMIDE SOLUTION MAGNESIUM S None ACETYL SALICYLIC ACID S When Fresh None; MAGNESIUM HYDROXIDE S None As It Ages Vinegar MANGANESE S None ADIPOYL CHLORIDE S Offensive Stench MANGANESE DIOXIDE S None ADIPOYL CHLORIDE/ S Hexane-like MERCURY S None HEXANE SOLUTION MOLYBDENUM (IV) OXIDE S None ALUMINUM NITRATE S/L Very Slight Ammonia NEUTRAL RED S None AMMONIA L/GAS Strong Ammonia NICHROME, WIRE S None AMMONIUM ACETATE S Weak Ammonia NICKEL S None AMMONIUM BROMIDE S Faint Ammonia ONION’S FUSIBLE ALLOY S None AMMONIUM CARBONATE S/L Strong Ammonia ORCEIN S None AMMONIUM HYDROXIDE L Strong Ammonia PHENYLHYDRAZINE S Strong Chlorine AMYL ACETATE L Banana-like HYDROCHLORIDE n-AMYL ALCOHOL L Banana-like PLATINUM WIRE S None ANILINE L Hard to characterize. POTASH, SULFURATED S Rotten Eggs A very slight benzene-like odor POTASSIUM (NEW) S None ANTIMONY TRICHLORIDE L Slight Chlorine POTASSIUM PERMANGANATE S None SOLUTION PUMICE S None ASPIRIN, TABLETS S Slight Vinegar RESAZURIN S/L None BALSAM S Sweet, Cedar-like SILICON S None BENZALDEHYDE L Almond SILVER S None BENZENE L Gasoline-like SILVER ACETATE S Slight Vinegar BENZOIC ACID S Maple Syrup SILVER CHLORIDE S Slight Chlorine BENZOPHENONE S Sweet; Rose-like SILVER OXIDE S None BENZYL ALCOHOL L Slight Floral SODIUM S None or Kerosene BISMUTH NITRATE S Stinging; Acid-like “dri-NA” S None BISMUTH NITRATE SOLUTION L Slight Nitric Acid STEEL S None BIURET S Vomit THERMIT S None BLOOD AGAR BASE INFUSION S Putrid Beef TIN S None BISMUTH NITRATE S/L Slight Nitric Acid WINKLER’S SOLUTION #1 L None BOUIN’S SOLUTION L Slight Formaldehyde WOOD’S METAL S None BROMOBENZENE L Like Moth Balls ZINC S None n-BUTYL ALCOHOL L Like Strong Wine sec-BUTYL ALCOHOL L Like Rubbing Alcohol *CLEAR, WHITE, MILKY, BUFF, NONE tert-BUTYL ALCOHOL L Camphor *Remember, if the chemical color is clear, white, milky, buff or none and the BUTYL STEARATE S Faint, Fatty Odor chemical does not have an odor, it will not appear on this list. BUTYRIC ACID L Penetrating, Obnoxious ACACIA S Slightly Musty Odor Like Vomit ACETALDEHYDE L Pungent; Fruity CADMIUM NITRATE S/L Slight Nitric Acid ACETAMIDE S Mousy; Musty CALCIUM ACETATE S Slight Vinegar ACETIC ACID L Pungent Odor; Like CALCIUM HYPOCHLORITE S Chlorine-like Vinegar CALCIUM IODIDE S Iodine-like ACETIC ACID, DILUTE L Vinegar CARBON DISULFIDE L Rotten Eggs ACETIC ANHYDRIDE L Strong Vinegar CARBON TETRACHLORIDE L Sweet; Something ACETONE L Sweetish; Like Finger- Like Bug Spray nail Polish Remover d-CAMPHOR S Penetrating, Aromatic; ACETYL CHLORIDE S Pungent; Vinegar-like Like a Chest Rub

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CHEMICAL COLOR /ODOR IDENTIFICATION CHART

SUBSTANCE Physical State Odor SUBSTANCE Physical State Odor *CLEAR, WHITE, MILKY, BUFF, NONE—continued *CLEAR, WHITE, MILKY, BUFF, NONE—continued *Remember, if the chemical color is clear, white, milky, buff or none and the HEXYL ALCOHOL L Strong; Flower-like chemical does not have an odor, it will not appear on this list. HYDROCHLORIC ACID L Very Strong Chlorine CARNOY’S SOLUTION L Alcohol-like HYDROGEN SULFIDE SOLUTION L Strong Rotten Eggs CELLULASE S Ginger ISOBUTYL ALCOHOL L Strong; Alcohol-like CETYL ALCOHOL S Faint; Citrus-like ISOPENTYL ALCOHOL L Strong; Disagreeable; CHLORETONE S/L Like a Chest Rub Alcohol-like CHLORINE L Pungent; Like Odor ISOPROPYL ALCOHOL L Rubbing Alcohol Around Swimming Pool KEROSENE L Oil CHLOROFORM L Sweet; Anesthesia-like LANTHANUM NITRATE S/L Slight Nitric Acid CLEANER, FLINN-IT L Soap-like LATEX L Slight Ammonia COLLODION L Strong Ether LAURIC ACID S Candle Wax CYCLOHEXANE L Rubber Cement-like LAUROYL PEROXIDE S Candle Wax CYCLOHEXANOL L Camphor-like LEAD ACETATE S Strong Vinegar CYCLOHEXENE L Paint Thinner LEAD ACETATE SOLUTION L Slight Vinegar DECANOIC ACID S Fresh Paint-like LEAD NITRATE S Slight Nitric Acid DEXTROSE AGAR S Dry Dog Food LIPASE S Decaying Flesh DIASTASE OF MALT S Gingerbread LULL-A-FLY S Licorice DIATOMACEOUS EARTH S Slightly Spicy LYSOZYME S Sewage DIBROMACETIC ACID S Faint Vinegar MAGNESIUM ACETATE S Slight Vinegar 1,4-DICHLOROBENZENE S Moth Balls MAGNESIUM IODIDE S Faint Iodine DIGITONIN S Malt-like MALEIC ACID S Faint Tea DIISOPROPANOLAMINE S Leather MALONIC ACID S Faint Beef Bouillon DIMETHYLGLYOXIME S Yogurt-like MALTOSE S Fresh Cut Hay DIMETHYLGLYOMINE L Alcohol MANGANOUS NITRATE L Faint Nitric Acid DIMETHYL SULFOXIDE L Smoked Oysters MENTHOL S Cooling to Nasal 1,4-DIOXANE L Ether-like Senses DIPHENYLAMINE S Strong Floral MERCURIC NITRATE S Faint Nitric Acid DITHIZONE REAGENT L Slight Chloroform MERCURIC SULFATE S Faint Nitric Acid

DODECYL ALCOHOL S Flower-like DL-METHIONINE S Like Odorized ETHER, ETHYL L Aromatic, Sweet Natural Gas ETHYL, ACETATE L Strong and More 2-METHOXY ETHANOL L Alcohol Pungent than Acetone METHYL ALCOHOL L Alcohol ETHYL, ALCOHOL L Alcohol METHYL ETHYL KETONE L Nail Polish Remover ETHYLENE DIAMINE L Ammonia METHYL ISOBUTYL KETONE L Sweet; Ether-like ETHYLENE DICHLORIDE L Chloroform-like METHYL METHACRYLATE L Strong Banana Oil ETHYLENE GLYCOL L Auto Anti-Freeze POLYMETHYL METHACRYLATE S Plastic FAA SOLUTION L Alcohol METHYL SALICYLATE L Wintergreen FORMALDEHYDE L Formaldehyde METHYLENE CHLORIDE L Ethyl Ether-like FORMALIN L Formaldehyde MILLON REAGENT SOLUTION L Slight Nitric Acid FORMIC ACID L Penetrating; Strong MOLISCH REAGENT L Alcohol-like Vinegar-like MONOSODIUM GLUTAMATE S Slight Spice D (+) GALACTOSE S Malt NAPHTHALENE S Moth Balls GELATIN S Faint, Sour; NAPHTHALENE ACETIC ACID S Mixture of Moth Balls Animal-like and Vinegar GLUTARALDEHYDE L Distinct Chlorine NINHYDRIN S Fresh Paint GUAR GUM S Freshly Cut Grass NITRIC ACID L Suffocating; Unique HEMATOXYLIN S Slight Vinegar Odor n-HEPTANE L Paint Thinner NITRIC ACID, DILUTE L Slight Nitric Acid HEXAMETHYL-ENEDIAMINE S Ammonia NUTRIENT AGAR S Strong; Putrid HEXANES L Paint Thinner NUTRIENT BROTH S Strong; Putrid

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SUBSTANCE Physical State Odor SUBSTANCE Physical State Odor *CLEAR, WHITE, MILKY, BUFF, NONE—continued *CLEAR, WHITE, MILKY, BUFF, NONE—continued *Remember, if the chemical color is clear, white, milky, buff or none and the SODIUM AMMONIUM S Faint Ammonia chemical does not have an odor, it will not appear on this list. PHOSPHATE 1-OCTADECANOL S Soap SODIUM BISULFITE S Faint Sulfur 2-n-OCTANOL S Strong; Floral SODIUM DIPHENYL- S Flower-like 1-n-OCTANOL L Strong; Floral AMINE SULFONATE OLEIC ACID L Wax-like SODIUM DITHIONITE S Strong Sulfurous PALMITIC ACID S Wax-like SODIUM IODATE S Faint Iodine PANCREATIN S/L Sour Malt SODIUM META-BISULFITE S Sulfur-like PARA-FORMALDEHYDE S Strong Formaldehyde SODIUM OLEATE S Soap-like PENTANE L Gasoline-like SORBIC ACID S Ginger PEPPERMINT OIL L Peppermint STEARIC ACID S Faint Wax PEPSIN S Sour Malt STYRENE, MONOMER L Aromatic; Rubber Cement-like PETROLEUM ETHER L Like Natural Gas SUCROSE S Malt-like PHENOL S/L Disinfectant SULFURIC ACID (REAGENT) L Sulfur; Sulfurous PHENOLPHTHALEIN S/L Alcohol l-TARTARIC ACID S Slight Malt PHENYL SALICYLATE S Disinfectant TETRAHYDROFURAN L Ether-like PHENYL THIOCARBAMIDE S Garlic-like THIOACETAMIDE S/L Buttered Popcorn POTASSIUM ACETATE S Slight Vinegar THYMOL S Liniment-like POTASSIUM BISULFATE S Peanut Brittle THYMOLPHTHALEIN INDICATOR L Alcohol POTASSIUM BROMATE S/L Slight Bromine TOLUENE L Benzene-like POTASSIUM CYANIDE S Slight Almond TRICHLOROACETIC ACID S Vinegar-like POTASSIUM IODATE S/L Strong Iodine 1,1,1-TRICHLOROETHANE L Chloroform-like POTATO DEXTROSE AGAR S Sour Mash TRICHLOROETHYLENE L Chloroform-like PROPIONIC ACID L Rancid and Vinegar 1,1,2-TRICHLORO L Carbon n-PROPYL ALCOHOL L Alcohol TRIFLUOROETHANE Tetrachloride-like PYRIDINE L Unique and Entirely Disagreeable TRIPHENYL TETRAZOLIUM S Unsalted Butter CHLORIDE RENNIN S Sour Mash RESORCINOL S Strange and Unique— TRYPSIN S Sour, Dry Urine Floral TRYPTONE S Malt SABOURAUD DEXTROSE AGAR S Sour Malt TURPENTINE L Paint Thinner SAPONIN S New Plastic UREASE S Soy Bean-like SCHIFF REAGENT L Strong Rotten Eggs VINEGAR (WHITE) L Acetic Acid SEBACOYL CHLORIDE L Suffocating Acid XYLENES L Airplane Glue SILICIC ACID S Faint Floral D (+) XYLOSE S Brown Sugar SILVER NITRATE S Faint Nitric Acid ZINC ACETATE S Faint Acetic Acid SODIUM ACETATE S Faint Vinegar ZINC STEARATE S New Leather

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