The sulphate of a metal `M` contains `9.87%` of `M`, This sulphate is isomorphous with `ZnSO_(4).7H_(2)O`. The atomic weight of `M` is

Options

A. 40.3
B. 36.3
C. 24.3
D. 11.3

Answer

C

Explanation

As the given sulphate is isomorphous with `ZnSO_(4).7H_(2)O` its formula would be `MSO_(4).7H_(2)O.m` is the atomic weight of M, molecular weight of `MSO_(4).7H_(2)O = m + 32 + 64 + 126 = m + 222`
Hence % of `M = m/(m + 222) xx 100 = 9.87` (given) or 100 m = 9.87m + `222 xx 9.87` or 90.13 m = `222 xx 9.87` or `m = (222 xx 9.87)/90.13 = 24.3`