Applying law of equivalence Equivalence of acid = Equivalence of base Equivalent of acid = Normality × volume =0.1×V Another formula of equivalence =n factor × number of moles ∴ Equivalent of base =n factor of OH−× moles of OH =1×0.04 0.1×V=1×0.04 V=0.4L=0.4×1000=400mL.