Equivalent weight of H3PO2(molecular weight =m ) when it disproportionates into PH3 and H3PO3\tM\tM/2\tM/4\t3M/4

Hi,

The answer is M.
Equivalent weight is weight of compound (M) here divided by change in oxidation state. As the compound is dissociating into two different products so we have top take average of valency on the product side which is 0. So in H3PO2 ist 1.
m/(1-0)=m