Na2CO3106+2HCl2×36.5→2NaCl+H2O+CO2
Eq. mass 531 g eq. 36.51 g eq.
CaCO3100+2HCl2×36.5→CaCl2+H2O+CO2
Eq. mass 501 g eq. 36.51 g eq.
Let x g CaCO3 be present in the mixture.
Mass of Na2CO3 in the mixture =(1.03−x)g
No. of g equivalent of CaCO3=x50
No. of g equivalents of Na2CO3=(1.03−x)53
No. of g equivalents in 20 mL N HCl=Normality×Vol.1000
=1×201000=150
At equivalence point,
No. of g equivalent of CaCO3+ No. of g equivalent of Na2CO3= No. of gram equivalent of HCl
x50+1.03−x53=150
or x=0.50
CaCO3=0.50 g, % CaCO3=0.501.03×100=48.54
Na2CO3=0.53 g, % Na2CO3=0.531.03×100=51.46.