Question

Write one point of difference between each of the following :
(i) A hydrated salt and an anhydrous salt
(ii) Washing soda and soda ash
(ii) Baking soda and Baking powder.

Answer 1

(i) Hydrated salt is a salt with water as water of crystallisation whereas Anhydrous salt is the salt which gives away its water of crystallisation.
(ii) Washing soda is sodium carbonate having ten molecules of water crystallisation $\left(N{a}_{2}C{O}_3.10H_{2}O\right)$ and hence anhydrous, whereas soda ash is sodium carbonate $\left(N{a}_{2}C{O}_3\right)$.
(iii) Baking soda is sodium bicarbonate $\left(NaHC{O}_3\right)$ whereas baking powder is a mixture of baking soda $\left(NaHC{O}_3\right)$ and tartaric acid $\left(C_4{H}_6{O}_6\right)$.