Question

Which of the following does not contain water of
crystallisation?
(a) Gypsum
(b) Plaster of Paris
(c) Hydrated copper sulphate
(d) Bleaching powder​

Answer 1

Answer:

The answer will be Bleaching powder (option D).

Explanation:

Water of  crystallization is the amount (or, moles) of water required to make a unit formula of a salt.

For example, CuSO4.5H2O is Blue Vitrol. Here, 5H2O is the water of crystallization in blue vitrol.

Formula:

1. Gypsum = CaSO4.2H2O

Here, 2H2O represents water of crystallization.

2. Plaster of Paris = CaSO4.1/2H2O

Here, 1/2H2O represents water of crystallization.

3. Hydrated Copper Sulphate = CuSO4.5H2O

Here, 5H2O represents water of crystallization.

4. Bleaching Powder = CaOCl2

Here, nothing is present to represent water of crystallization. Thus, this is our answer.

That's all.