Temporary hardness of water can be removed by:

1. Adding sodium chloride
2. Boiling
3. Adding calcium carbonate
4. Leaving it for a few hours.

The salt which does not contain any water of crystallisation is :

P — Blue vitriol

Q — Gypsum

R — Baking soda

1. Only P
2. Only Q
3. Only R
4. Both Q and R

The figure shown below demonstrates the solubility curve of a substance. From the statements given below, choose which is/are correct :

P — A is hydrated sodium chloride, B is anhydrous sodium chloride.

Q — A is Glauber's salt, B is sodium sulphate.

R — A is Gypsum, B is calcium sulphate.

1. Only P
2. Only Q
3. Only R
4. Both P and R

Assertion (A): Water is a universal solvent.

Reason (R): Water dissolves all substances except noble metals and glass.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.