[IBM]

As we know, Equivalent weight = molecular weight/number of H+ replaced
So, in H2SO4, E = M/2 = 98/2 = 49g/equivalent of H+
1.  But in this reaction, NaOH + H2SO4 = NaHSO4 + H2O how to calculate the equivalent weight of H2SO4?
2. 2NaOH + H3PO4 = Na2HPO4 + H2O, How to calculate the equivalent weight of 'H3PO4'?

[mjc123]

Try applying the equation in the first line of your post.
Note that for polybasic acids, there is no such thing as the equivalent weight. It depends on the reaction, and how many Hs are replaced.

[Vidya]

As we know, Equivalent weight = molecular weight/number of H+ replaced
So, in H2SO4, E = M/2 = 98/2 = 49g/equivalent of H+
1.  But in this reaction, NaOH + H2SO4 = NaHSO4 + H2O how to calculate the equivalent weight of H2SO4?
2. 2NaOH + H3PO4 = Na2HPO4 + H2O, How to calculate the equivalent weight of 'H3PO4'?

It  is also defined as molar mass /electrons transferred