Dehydration of salts is an important class of heterogeneous reactions. The salt hydrates during dehydration often dissociate in steps to form a number of intermediate hydrates according to the prevailing pressure of moisture in contact with the solid hydrates. Thus, copper sulphate pentahydrate on dissociation yield trihydrates, monohydrates and then the anhydrous salt in the above order as follows:

The equilibrium constant `K_(p)` for the equilibrium between pentahydrate and trihydrate is:

Options

A. 7.8
B. 60.84
C. 31.36
D. 5.6

Answer

B

Explanation

`CuSO_(4).5H_(2)O rarr CuSO_(4).3H_(2)O + 2H_(2)O(g)`
`P_(H_(2)O) = 7.8 mm implies K_(p) = (P_(H_(2)O))^(2) = (7.8)^(2) = 60.84`