Question

Anhydrous white substance used for the detection of presence of water in an environment which is associated with 56.25 % of increase in weight after hydration. Find out the number of water of crystallization after hydration if the molecular weight of anhydrous substance is 160 gms.

• A. 5
• B. 123
• C. 112
• D. 32

Answer 1

The correct option is A 5

After hydration weight increases by 56.25%. Compound has molecular weight of 160 gm and after hydration, its weight becomes $\frac{56.25\times 160}{100}=90$.

Let n be the number of water molecules associated with compound and water molecules has weight of 90 gm. So, number of water molecules $\frac{90}{18}=5$.