In chlorine,the isotopes $^{35}Cl$ and $^{37}Cl$ are present in the ratio $3:1$. Calculate the atomic mass of chlorine. (in $amu$)

$A$ mixture of $1.65 \times 10^{21}$ molecules of $X$ and $1.85 \times 10^{21}$ molecules of $Y$ weighs $0.688 \ g$. If the molecular mass of $Y$ is $187 \ g/mol$,what is the molecular mass of $X$?

Match column $-I$ and column $-II$ with the correct molar mass values:

Column $-I$	Column $-II$
$(i)$ Barium sulphate	$(a)$ $1877 \ g/mol$
$(ii)$ Magnesium pyrophosphate	$(b)$ $235 \ g/mol$
$(iii)$ Ammonium phosphomolybdate	$(c)$ $188 \ g/mol$
$(iv)$ Silver chloride	$(d)$ $222 \ g/mol$
$(v)$ Silver bromide	$(e)$ $143.5 \ g/mol$
$(vi)$ Silver iodide	$(f)$ $233 \ g/mol$

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

$12 \ g$ of an element reacts with $32 \ g$ of oxygen. What is the equivalent weight of the element?

The equivalent mass of iodine in the following reaction is $I_2 + 2S_2O_3^{2-} \longrightarrow 2I^{-} + S_4O_6^{2-}$