# 40 g of an unknown metal combines with 2 g of hydrogen to form its corresponding hydride. What is the equivalent weight of the metal? If the metal is divalent, find the atomic weight of the element.

Weight of metal = 40 g
Weight of hydrogen =2g
40 g of metal $\qquad\underrightarrow{combines\;with}\qquad 2 g of H$
Eq.wt.of metal $\qquad\underrightarrow{combines\;with}\qquad 1g of H$
Eq.wt of metal =$\large\frac{1\times 40}{2}$$=20$
We also know, Eq. wt. =Atomic weight/valency
Atomic weight=Eq.wt$\times$ valency=$20\times 2=40$
Therefore, atomic weight of the element is 40
Hence (A) is the correct answer.