$8 \ g$ of a metal reacted with oxygen to form $9 \ g$ of its oxide. What is the weight (in $g$) of the metal required to react with $8 \ g$ of hydrogen? $(H=1.0)$

An element $X$ reacts with oxygen to form a compound $X_2O_3$. If the atomic mass of $X$ is $91.5$,the equivalent mass of $X$ is:

If $74.5 \ g$ of a metallic chloride contains $35.5 \ g$ of chlorine,then the equivalent mass of the metal will be ...... .

What are the equivalent weights of $H_3PO_4$ in the following reactions respectively?
$H_3PO_4 + OH^{-} \rightarrow H_2PO_4^{-} + H_2O$
$H_3PO_4 + 2OH^{-} \rightarrow HPO_4^{2-} + 2H_2O$
$H_3PO_4 + 3OH^{-} \rightarrow PO_4^{3-} + 3H_2O$

The equivalent weight of which of the following is maximum? (Given: atomic weights $Na=23, Mn=55, Cr=52, K=39, O=16, C=12$)

The equivalent mass of an element $X$ is $9$. If the vapor density of its chloride salt is $66.75$,determine the valency of element $X$.