$1 \ u \ (amu)$ is equal to

$1.520 \ g$ of the hydroxide of a metal on ignition gave $0.995 \ g$ of oxide. The equivalent weight of the metal is:

Which method is used to determine atomic mass accurately?

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:

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	$(f)$ $233 \ g/mol$

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