Question

The specific heat of a metal $M$ is $0.25$. Its equivalent weight is $12$. Then, its valency is :

Answer 1

According to Dulong Petit's Law,

Specific heat$\times$atomic weight$=6.4$.

Atomic weight $=\frac{6.4}{0.25}=25.6$.

So, valency $=\frac{atomicweight}{equivalentweight}=\frac{25.6}{12.0}=2.13\approx 2$.

Thus,

(i)$M^{2+}+C{l}^{-}\to MC{l}_2$ .

(ii)$M^{+2}+S{O}_4^{-2}\to MS{O}_4$ .

Similarly
(iii)$M_3(P{O}_4{)}_2$.