Question

equivalent weight of H3PO2 when it disproportionate into PH3 &H3PO3 is??

Answer 1

The reaction proceeds as,
3H₃PO₂ -----> PH₃ + 2H₃PO3
Equivalent weight = molecular weight / n-factor
n- factor = Number of electrons transfered in the reaction ( lost/ gain)/ total number of moles in balanced reaction
If we consider the number of electron gain by the reaction then,
H₃PO₂ →PH₃
Change of oxidation state is from +1 to -3. That is total gain of 4 electrons.
Therefore n will be = 4/3
Hence the equivalent wt. will be 3M/4 = 66g x 3/4 = 49.5 g