The amount of $K_2Cr_2O_7$ (equivalent weight $49.04$) required to prepare $100 \ mL$ of its $0.05 \ N$ solution is ........ $g$.

In a reaction,the ferrous $(Fe^{2+})$ ion is oxidized to ferric $(Fe^{3+})$ ion. The equivalent weight of the ion in the above reaction is equal to:

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 oxide of a metal contains $40 \%$ of oxygen. The valency of the metal is $2$. What is the atomic weight of the metal?

$1 \ amu$ is equal to

Which of the following is true about sodium chloride?