(a) The neutralisation equivalent (NE) is the equivalent weight (g/eq) of an acid as determined by titration with standardized NaOH.
(b) The no. of ionizable H's of an acid is the no. of equivalents per mole, and is equal to Mw/NE.
Here, the no. of equivalents (No. of ionizable H's)=210ℊ/㏖70ℊ/eq=3eq/㏖
The no. of equivalent of NaOH equals the no. of ionizable H's, in this case 3eq/mol.
(c) The neutralization equivalent of mellitic acid is
NE=MwNo.ofionizableH′s=342ℊ/㏖6eq/㏖=57ℊ/eq