A solution of a salt of a metal of atomic weight $'\lambda'$ was electrolysed for 150minutes with 0.15A of current .The weight of metal deposited was 0.783g.Find X,the specific heat of metal=0.057Cal/$g^{\large\circ}C$.According to Dulong-Petit's law,approximate atomic weight of a metal $X$ specific heat=6.4

Question

$\begin{array}{1 1}(a)\;101.86gm/mol\\(b)\;120.86gm/mol\\(c)\;96.86gm/mol\\(d)\;111.86gm/mol\end{array}$