In a Victor Meyer's apparatus,$510 \ mg$ of a liquid on vaporization displaces $67.2 \ cm^3$ of dry air at $NTP$. What is the molecular weight of the liquid?

An element,$X$ has the following isotopic composition:
$^{200}X: 90\%$,$^{199}X: 8.0\%$,$^{202}X: 2.0\%$
The weighted average atomic mass of the naturally occurring element $X$ is closest to......$amu$.

The weight of $1 \ L$ of an unknown gas at $N.T.P.$ is $1.25 \ g$. Which of the following gases can be identified from the given information?

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

If $m_1 \ g$ of metal $A$ displaces $m_2 \ g$ of another metal $B$ from its salt solution,and their equivalent weights are $E_1$ and $E_2$ respectively,how is the equivalent weight of $A$ expressed?

$0.1$ mol of the following given antiviral compound $(P)$ will weigh $......... \times 10^{-1} \ g$
$Given :$ molar mass in $g \ mol^{-1} H: 1, C: 12, N: 14, O: 16, F: 19, I: 127$