Question

Which of the following is incorrectly matched?

Salt	Water of crystallization
(i) Blue vitriol	$5$
(ii) Washing soda	$10$
(iii) Gypsum	$2$
(iv) Baking soda	$1.5$

• A. (ii)
• B. (iv)
• C. (i)
• D. (iii)

Answer 1

The correct option is B (iv)

Water of crystallization refers to the number of water molecules present in the salt.
The chemical formula for the given compounds are
Blue vitriol - $CuS{O}_4.5H_{2}O$ , water of crystallization is 5.
Washing soda - $N{a}_{2}C{O}_3.10H_{2}O$, water of crystallization is 10.
Gypsum - $CaS{O}_4.2H_{2}O$, water of crystallization is 2
Baking soda - $NaHC{O}_3$.It has zero water molecules.
Hence, the correct choice is option (iv)