As given, NaOH and Na2CO3 is titrated with N∕10HCl. For NaOH, Equivalents of NaOH= Equivalents of HCl Equivalents of HCl= Normality × Volume (L) =0.1×
17.5
1000
Equivalent of HCl=1.75×10−3 Equivalents of NaOH=1.75×10−3 Weight of NaOH= Equivalent of NaOH× equivalent weight of =40×1.75×10−3=0.07g NaOH Now, weight % of NaOH =
0.07
0.4
×100=
70
4
=17.5% Similarly for Na2CO3, Equivalent of HCl= Equivalent of Na2CO3 Equivalent of Na2CO3=0.1×
1.5
1000
=0.15×10−3 Weight of Na2CO3= Equivalent of Na2CO3× equivalent weight of Na2CO3 =0.15×10−3×106=15.9×10−3g Weight \% of Na2CO3=