← Back to the activity

Class 10 Science — Acids, bases and salts

Predict what an acid gives with a metal, a carbonate and a base, read a solution's nature off the pH scale, and name the salts that common salt is turned into.

Name: ________________________

  1. 1.Blue copper sulphate crystals are heated until they turn white, and droplets of water collect in the tube. How many water molecules does one formula unit of the hydrated salt hold? Answer with a number.

  2. 2.Match each natural source to the acid the chapter names in it.

    • Vinegar
    • Lemon
    • Tamarind
    • Tomato
    • Curd
    • An ant sting
    • Oxalic acid
    • Acetic acid
    • Lactic acid
    • Tartaric acid
    • Methanoic acid
    • Citric acid

  3. 3.Bleaching powder is made from chlorine and one other substance. Which?

    • a) Common salt
    • b) Washing soda
    • c) Plaster of Paris
    • d) Dry slaked lime

  4. 4.Common salt is turned into bleaching powder in stages. Put them in order, beginning with "Brine, common salt dissolved in water".

    • Bleaching powder
    • Chlorine given off at the anode
    • An electric current passed through the brine
    • Chlorine acting on dry slaked lime
    • Brine, common salt dissolved in water

  5. 5.Sort each of these by whether the chapter treats it as acidic or as basic.

    Groups: Acidic · Basic

    • Milk of magnesia
    • The sting left by a bee
    • Toothpaste
    • Gastric juice in the stomach
    • A solution of baking soda
    • The stinging hair of a nettle leaf

  6. 6.A strip of pH paper scale is drawn below, running from 0 at the left to 14 at the right. Tap the stretch a basic solution would read in.

    Write the number of the part.

    123

  7. 7.Baking powder is baking soda mixed with tartaric acid. What makes a cake rise when the powder is heated?

    • a) Steam given off by the tartaric acid
    • b) Air whisked into the batter beforehand
    • c) Hydrogen given off by the reaction
    • d) Carbon dioxide given off by the reaction

  8. 8.Solution P has a pH of 6 and solution Q has a pH of 8. Which statement is right?

    • a) P has more hydrogen ions, and P is the acidic one
    • b) They hold the same number of hydrogen ions
    • c) Q has more hydrogen ions, and Q is the acidic one
    • d) P has more hydrogen ions, and Q is the acidic one

Answer key — Class 10 Science — Acids, bases and salts

  1. 1. 5
  2. 2. Vinegar → Acetic acid; Lemon → Citric acid; Tamarind → Tartaric acid; Tomato → Oxalic acid; Curd → Lactic acid; An ant sting → Methanoic acid
  3. 3. d) Dry slaked lime
  4. 4. 1. Brine, common salt dissolved in water 2. An electric current passed through the brine 3. Chlorine given off at the anode 4. Chlorine acting on dry slaked lime 5. Bleaching powder
  5. 5. Gastric juice in the stomach → Acidic; The sting left by a bee → Acidic; The stinging hair of a nettle leaf → Acidic; Milk of magnesia → Basic; Toothpaste → Basic; A solution of baking soda → Basic
  6. 6. 3 — Above 7 — basic
  7. 7. d) Carbon dioxide given off by the reaction
  8. 8. a) P has more hydrogen ions, and P is the acidic one