Question

The cupric salt (${Cu}^{2+}$) of a monobasic acid contains 3 molecules of water of hydration per atom of Cu. 1 g of hydrated salt on strong heating yields 0.3306 g of CuO. The equivalent mass of acid is (as the nearest integer) :

Answer 1

In general, the gram-equivalent weight of a salt in which a change of valence does not occur during the reaction is equal to its gram-formula weight divided by the total charge of all positive ions (or of all negative ions).

Eq. of Cu salt $=$ Eq. of CuO

$\frac{1}{E}=\frac{0.3306}{79.5/2}$
$E=13.14$
So, nearest integer is $13$.