Question

Equivalent weight of H3PO2 when it disproportionate into PH3 and H3PO3 is :-

Answer 1

so frnd ur answer is --

For disproportionation reactions, use a trick to find equivalent mass; E = E1 + E2; where E1 and E2 are equivalent masses of oxidation and reduction half reactions of same element.

Now, find the n-factor(total change in oxidation number per molecule) and then equivalent mass = molar mass/n-factor.

So, when H3PO2 changes into PH3, oxidation state of phosphorous changes from +1 to -3 so as n-factor is 4. Also when H3PO2 changes into H3PO4, oxidation state of phosphorous changes from +1 to +5 so as n-factor is again 4.

Now equivalent mass of H3PO2, E =(M/4) + (M/4) = M/2

hope it helps u!!!☺

Answer 2

Answer:

3M/4

Explanation:

3H3PO2 ------PH3 +2H3PO3

WE have equivalent weight=molecular weight/n factor

for such type of redox reaction the n factor is calculated as

no of electron exchanged/total number of mole used

H3PO2-------PH3

change in oxidation number is from 1 to -3 .Thus 4e- are used

from 2H3PO2 ----2H3PO2

Change in oxidation number is from 1 to +3 therefore electron given is 2e-.for 2 moleculae of H3PO2 thus 4 lectron are used

thus in total 4e- are exchanged

n factor=no of electron/no of mole=4/3

Thus the eq weight=M/(4/3)=3M/4 .