SCH 3U Double Displacement Reactions

Soluble ionic compounds dissociate (separate) in solution. This process can be represented by a dissociation equation.

+ - 3+ - NaOH(s)  Na (aq) + OH (aq) FeCl3(s)  Fe (aq) + 3Cl (aq)

Soluble covalent compounds (mostly acids) ionize(produce ions) in solution.. This process can be represented by an ionization equation.

+ - + 2- HCl(aq)  H (aq) + Cl (aq) H2SO4(aq)  2H (aq) + SO4 (aq)

**notice that subscripts will only be present if they are part of the formula of a polyatomic ion (never associated with hydrogen or metal ions)

Ionic compounds which dissociate & covalent compounds which ionize are said to be electrolytes  they are substances that conduct electricity in solution.

**in order to conduct electricity, a solution must contain freely moving charged particles.

 Strong electrolytes – dissociate or ionize completely  Weak electrolytes – dissociate or ionize only slightly

Non-electrolytes are substances which do not conduct electricity in solution.

You can determine whether an ionic compound will dissociate by consulting a solubility table or the solubility rules.

Except with these Category Ions Examples ions

Group 1 metallic ions Na2CO3, LiOH, and Soluble cations + No exceptions and ammonium, NH4 (NH4)2S are soluble.

 NO3 and Bi(NO3)3, and Soluble anions  No exceptions C2H3O2 Co(C2H3O2)2 are soluble. Soluble with some    Usually soluble Cl , Br , and I exceptions, including CuCl2 is water soluble, anions with but AgCl is insoluble. Ag+ and Pb2+ Soluble with some

2 exceptions, including FeSO4 is water soluble, SO4 with but BaSO4 is insoluble. Ba2+ and Pb2+

Insoluble with some CaCO3, Ca3(PO4)2, and

Usually insoluble 2 3  exceptions, including Mn(OH)2 are insoluble in water, CO3 , PO4 , and OH anions with group 1 elements but (NH4)2CO3, Li3PO4, and + and NH4 CsOH are soluble.

Solubility Table for Ionic Compounds in Water

+ + + 2+ 2+ 2+ 2+ 3+ 2+ 2+ 3+ 2+ 2+ 2+ + 2+ 2+ 2+ 3+ 2+ 4+ 2+ Anion / NH4 Na K Mg Ca Sr Ba Cr Mn Fe Fe Co Ni Cu Ag Zn Cd Hg Al Sn Sn Pb Cation F- S S S I I I * I * * * S S S S S S -- * S S I Cl- S S S S S S S S S S S S S S I S S S S S S * Br- S S S S S S S S S S S S S S I S S * S S S * I- S S S S S S S -- S S -- S S -- I S S I S S S I - NO3 S S S S S S S S S S S S S S S S S S S -- -- S - ClO3 S S S S S S S ------S S S S S S S S -- -- S - C2H3O2 S S S S S S S S S S -- S -- S S S S S ------S OH- S S S I * * S -- I I -- I I I -- I I -- I -- -- I S2- S S S S I * * I I I I I I I I I I I -- I I I 2- SO4 S S S S * I I S S * * S S S * S S -- S S S I 2- CO3 S S S I I I I -- I I -- I I -- I I I ------I 3- PO4 S S S I I I I -- -- I I I I I I I I -- I I -- I

S= SOLUBLE * = SPARINGLY SOLUBLE I= INSOLUBLE --SOLUBILITY DATA NOT AVAILABLE

Assignment For the following compounds, determine if the compound is soluble or not by referring to your solubility table. If the compound is soluble, complete a dissociation or ionization equation. (Assume that all acids are soluble)

1. potassium hydroxide 6. ammonium phosphate

2. iron (II) hydroxide 7. tin (IV) sulphate

3. calcium bromide 8. copper (II) acetate

4. potassium carbonate 9. iron (III) chloride

5. iron (II) sulphate 10. nitric acid Nonionic, complete ionic & net ionic equations

Balanced equation – ______

**the equation must be balanced before writing the complete or net ionic equations**

Total ionic equation – ______

Net ionic equation – ______

Spectator Ions ______

Rules for writing Double displacement Reactions 1. Write the skeletal equation with the physical states for reactants and products. 2. Balance the equation. 3. Write the total ionic equation (all substances that can dissociate/ionize) with proper states of matter. 4. Cross out spectator ions (those that remain in solution or not used in the reaction –electron transfer) on both sides of the reaction. 5. Write the net ionic equation (balanced, including charges on ions that are responsible for the reaction and the insoluble products of those reactions)

Example #1 Word Equation: Samples of solutions of barium chloride and sodium sulfate are mixed together to produce aqueous sodium chloride and barium sulfate.

Balanced Equation:

Total Ionic:

Net Ionic:

Example #2 Word equation: Samples of solutions of silver nitrate and sodium chloride are mixed together to produce a solid, silver chloride within the solution sodium nitrate.

Balanced:

Total Ionic:

Net Ionic