An aqueous solution of 6.3g oxalic acid dihydrate is made upto 250 ml. the volume of 0.1 N NaOH required to completely neutralise 10 ml of this solution is

Oxalic acid (H2C2O4 2H20) W = 6.3gGMW = 126gGEW = 126/2 = 63gN = 0.4 N10ml of this solution required Vml of 0.1N, NaOH (b) for complete neutralizationVa = 10ml          ;         Vb = ?Na = 0.4N          ;         Nb = 0.1NAt equivalent point,   VaNa = Vb Nb                            10(0.4) = Vb(0.1)                             Vb = 40mlvolume  of NaOH required = 40ml