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

If the equivalent mass of a metal with a valency of $+2$ is $12$,then the molar mass of its oxide is:

When the weights of two elements combine with each other,their ratio is the ratio of their ......

What is the atomic mass of $Fe$?
Given abundance of ${}^{54}Fe = 10\%$,${}^{56}Fe = 85\%$,and ${}^{57}Fe = 5\%$.

Atoms or groups of atoms which are electrically charged are known as:

Suppose the elements $X$ and $Y$ combine to form two compounds $XY_2$ and $X_3Y_2.$ When $0.1 \ mol$ of $XY_2$ weighs $10 \ g$ and $0.05 \ mol$ of $X_3Y_2$ weighs $9 \ g,$ the atomic weights of $X$ and $Y$ are