Question

In the reaction-
$H_3{PO}_4+Ca{\left(OH\right)}_2\to CaH{PO}_4+2H_{2}O$
the equivalent of phosphoric acid is-

• A. $32.7$
• B. $98.0$
• C. $49.0$
• D. $196.0$

Answer 1

The correct option is C $49.0$

In its most general usage, it is the mass of one equivalent, that is the mass of a given substance which will supply or react with one mole of hydrogen cations $H^{+}$ in an acid–base reaction.
So in the given reaction 3 hydrogen moles react to give one mole of hydrogen in the so it has 2 hydrogen mole therefore the equivalent mass is determined by dividing the molar mass by 2