The mass of 70% H2SO4 required for neutralization of one mole of NaOH is

nNaOH = 1moleNo.of equivaents of NaOH = 1Number of eq of H2SO4 = Number of eq of NaOHWt of 100% pure H2SO4 required = 49gWt of 70% pure H2SO4 required = 49 x 100/70                                                 = 70g