Chapter 11 Salts
Answers to Textbook Exercises
Quick Check (page 164) Quick Check (page 165) Quick Check (page 168)
a) Nitric acid (a) Yes (a) No. Copper is too unreactive
b) Hydrochloric acid (b) No (b) Yes. Hydrogen gas is given off
c) Sulphuric acid (c) Yes during the reaction.
d) Phosphoric acid (d) Yes (c) No. Lead is too unreactive.
e) Ethanoic acid (e) Yes (d) No. Sodium is too reactive.
The reaction is explosive.
Test Yourself 11.1 (page 173)
1. A: dilute nitric acid B: water C: zinc (or dilute sulphuric acid)
D: dilute sulphuric acid (or zinc) E: dilute hydrochloric acid F: carbon dioxide
2. Using magnesium oxide and dilute sulphuric acid (See textbook section 11.2 Method 1)
• Dissolve an excess of solid magnesium oxide in dilute sulphuric acid. Magnesium sulphate is formed. It is a soluble salt.
• Filter the mixture and collect the soluble salt as the filtrate. Excess magnesium oxide is collected as the residue.
• Concentrate the filtrate by evaporation (gentle heating with a Bunsen flame).
• Cool the saturated solution. Crystals of magnesium sulphate start to form on the evaporating dish.
• Filter to remove any excess filtrate.
• Dry the crystals between sheets of filter paper.
3. Using potassium hydroxide and dilute sulphuric acid (See textbook section 11.2 Method 2)
• Pour dilute sulphuric acid into a burette.
• Pipette 25 cm3 of potassium hydroxide solution into the conical flask. Add two drops of methyl orange. The solution turns yellow.
• Add dilute sulphuric acid from the burette slowly until the solution just turns red.
• Record the volume of dilute sulphuric acid used (V cm3).
• Now pipette 25 cm3 of potassium hydroxide into a new conical flask.
• Add V cm3 of dilute sulphuric acid into the potassium...