 No Brain Too Small  CHEMISTRY  AS 91165 IDENTIFYING ORGANIC COMPOUNDS miscible immiscible Insoluble in Slow reaction needing Reaction with + - • Alkanes UV light and/or heat: H /MnO4 Orange bromine water • Alkenes (a purple coloured slowly decolourised. • Alkynes solution) • • Haloalkanes Alkane • Purple permanganate is rapidly • Bigger alcohols, carboxylic • Haloalkane (I have never seen decolourised by an alkene (makes and amines (C4 and above this asked in NCEA!) a diol) approx.) Type of reaction: SUBSTITUTION Type of reaction: OXIDATION Fast reaction: Orange Soluble in water (C1-4/5 approx.) bromine water rapidly • Alcohols Reaction with bromine decolourised. • • Carboxylic acids Solubility in water? Alkene water, Br2(aq)? • • Amines Alkyne Type of reaction: ADDITION TESTS TO KNOW • Amine: turns red litmus paper Amines stink! Oh yes they do! blue; blue litmus stays blue. • Many smell like dead fish or Amines turn green UI solution Does it change the something decomposing..... blue. Other things that might • colour of litmus or Carboxylic : turns blue litmus be useful to know! paper red; red litmus stays red. Universal Indicator? Carboxylic acids turn green UI solution orange. amine carboxylic acid • Alcohol: Does not change red or Test for a primary • Carboxylic acids tend to have a blue litmus paper or green UI alcohol “sharp smell” e.g. ethanoic acid solution • Warm a sample with has vinegary smell and butanoic acidified dichromate acid smells like rancid butter..... solution • Carboxylic acid + carbonate + 2- (CaCO3) or H /Cr2O7 (aq) / heat • Colour change from orange carbonate (NaHCO3) - you 2- 3+ will see bubbles of gas. Cr2O7 to green Cr is seen. Type of reaction: OXIDATION Type of reaction: ACID- or NEUTRALISATION  No Brain Too Small  CHEMISTRY  AS 91165 IDENTIFYING ORGANIC COMPOUNDS

Examples of questions

Sodium hydrogen carbonate is added Five separate colourless organic liquids are known to be: to a sample of the following organic Ethanamine, propanol, pentane, hexan-1-ol, pent-1-ene, compound. Write a valid method to show how each of these liquids can be • Give the structure of the organic identified using only water, litmus paper, and bromine water, product formed. Br2(aq). • Describe the type of reaction occurring, giving a reason why it is Your method should allow another student to identify these classified as this type. liquids, and include: • the reagent used • any observations made. You do not need to include equations in your answer.

Two bottles containing pent-1-ene, CH3CH2CH2CH=CH2, and hexane, CH3CH2CH2CH2CH2CH3, require identification. – + Two reagents, bromine water, Br2, and acidified potassium permanganate, MnO4 / H , are available. Discuss the possible use of BOTH reagents to distinguish between the pent-1-ene and hexane. In your answer you should include: • a description of the type of reactions that would occur • any conditions that would be required • any observations that would be made • equations showing the structural formulae of the organic reactant(s) and product(s).