What is meant by $1 \ amu$ or $1 \ u$?

Sulphur forms the chlorides $S_2Cl_2$ and $SCl_2$. The equivalent mass of sulphur in $SCl_2$ is $...$ $g/mol$.

In the standardization of $Na_2S_2O_3$ using $K_2Cr_2O_7$ by iodometry,the equivalent weight of $K_2Cr_2O_7$ is:

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

If $0.228 \, g$ of silver salt of a dibasic acid gave a residue of $0.162 \, g$ of silver on ignition,then the molecular weight of the acid is:

$16.25 \ g$ of metal chloride is obtained on complete conversion of $8 \ g$ of metal oxide into metal chloride. What will be the equivalent weight of the metal?