Chapter 14:Salt and identification of Ions 

Salt

  • A salt is a compound that is formed when the hydrogen of an atom in an acid is replaced by a metal.

  • It is formed by the neutralisation reaction between an acid and a base

  • [ ] Precipitation

  • [ ] Titration

Reactions

  1. Metal and acid➡️ salt and water
  • [ ] zinc + sulphuric acid➡️ zinc sulphate+ Hydrogen

2. Metal oxide + acid ➡️ salt and water

  • [ ] Copper(II) oxide + sulphuric acid➡️ copper sulphate+ water

3• Metal hydroxide + acid ➡️salt and water

  • [ ] Potassium hydroxide+ hydrochloric acid ➡️ potassium chloride + water

4• Metal carbonate + acid ➡️salt+water+ carbon dioxide

  • [ ] Zinc carbonate+ nitric acid ➡️ zinc nitrate +water+ carbon dioxide

Solubility

Preparation of soluble salts

  1. Metal and acid
  2. Metal oxide and acid
  3. Metal hydroxide and acid(titration)
  4. Metal carbonate and acid

Preparation of insoluble salts

  • Precipitation

  • [ ] Soluble salt+ soluble salt ➡️ insoluble salt

Identification of ions

  • Cations (postive ions) they travel to the negative terminal Cathode during electrolysis.

  • Anions (negative ions) they travel to the positive terminal Anode during electrolysis

Identification of gases

HydrogenPops with a lighted splinter
OxygenRelights a glowing splinter
Carbon dioxideTurns limewater milky
ChlorineTurns moist blue litmus red and then bleaches it
AmmoniaTurns moist red litmus paper blue
Sulphur DioxideTurns acidified potassium dichromate from yellow to green