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

Consider the following data:

Element	Atomic mass
$A$	$12.01$
$B$	$35.5$

$A$ and $B$ combine to form a new substance $X$. If $4 \ mol$ of $B$ combine with $1 \ mol$ of $A$ to give $1 \ mol$ of $X$,then the weight of one mole of $X$ is ........... $g$.

$H_2SeO_4 + NaOH \to NaHSeO_4$; $E.W.$ of $H_2SeO_4 = E_1$
$H_2SeO_4 + 2NaOH \to Na_2SeO_4$; $E.W.$ of $H_2SeO_4 = E_2$
What is the relation between $E_1$ and $E_2$?

$2 \ g$ of metal carbonate is neutralized completely by $100 \ mL$ of $0.1 \ N$ $HCl$. The equivalent weight of metal carbonate is:

The present atomic weight scale is based on

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