Question

0.68g of a solid diprotic acid was dissolved in 30.0mL of a 0.50 NaOH sol'n. the resulting mixture was then back-titrated against 0.20 M HCl; 25mL were required. Calculate the molar mass of the acid. This acid is a solid salt of a triprotic acid, identify this acidic salt.

Answer 1

m/mm* n(H+) + [HCl] * Va*n(+)+) = [NaOH]*Vb*n(OH)
0.68g/mm*2 + [0.02M]*0.025L*1 = [0.5M]*0.03L*1
PO4=mol

Answer 2

I can't get the answer.
Can anyone help?