The equivalent weight of $H_3PO_4$ in the reaction $Ca(OH)_2 + H_3PO_4 \rightarrow CaHPO_4 + 2H_2O$ is

Chlorine exists in two isotopic forms $^{35}Cl$ and $^{37}Cl$. If the average atomic mass of chlorine is $35.5$,what is the percentage abundance of these isotopes respectively?

In the chemical scale,the relative atomic mass of the naturally occurring isotopic mixture of oxygen atoms $({}^{16}O, {}^{17}O, {}^{18}O)$ is taken as:

$1 \ g$ of a metal nitrate produces $0.86 \ g$ of metal sulphate. The equivalent weight of the metal will be:

Assertion : The normality of $0.3 \ M$ aqueous solution of $H_3PO_3$ is equal to $0.6 \ N$.
Reason : Equivalent weight of $H_3PO_3 = \frac{\text{Molecular weight of } H_3PO_3}{3}$

Which of the following properties of an element is not variable?