Question

Which of the following salts are not hydrated salts?

• A. Glauber's salt
• B. Washing soda
• C. Baking soda
• D. Blue vitriol

Answer 1

The correct option is C

Baking soda

Salts those contain water of crystallization are called hydrated salts.

Glauber's salt :- sodium sulphate decahydrate (${\text{Na}}_2{\text{SO}}_4.10{\text{H}}_2\text{O}$)

Blue vitriol:- Copper sulphate pentahydrate (${\text{CuSO}}_4.5{\text{H}}_2\text{O}$)

Washing soda:- Sodium carbonate decahydrate (${\text{Na}}_2{\text{CO}}_3.10{\text{H}}_2\text{O})$

The dot in the chemical formula indicates that the water molecule is in a loose chemical combination and can be removed upon heating.

The formula of baking soda is (${\text{NaHCO}}_3$) and it is evident from the formula that it does not contain water of crystallisation.