Which symbol replaced the unit of atomic mass,$amu$?

Equivalent weight of crystalline oxalic acid is ...........

$A$ metal oxide contains $32\%$ oxygen by mass. Its equivalent mass is:

If $M_1$ and $M_2$ are the molecular weights of $Al(OH)_3$ and $H_3PO_3$ respectively,find their equivalent weights in the following reaction:
$Al(OH)_3 + 2H_3PO_3 \to Al(OH)(H_2PO_3)_2 + 2H_2O$

One liter of hard water contains $12.00 \, mg$ of $Mg^{2+}$. How many milliequivalents of washing soda are required to remove its hardness?

The equivalent weight of phosphoric acid $(H_3PO_4)$ in the reaction $NaOH + H_3PO_4 \to NaH_2PO_4 + H_2O$ is