2.5 mL of 0.1 M H2SO4=2.5 mL of 0.2 N H2SO4
=12Na2CO3 present in 10 mL of mixture
So,
5 mL of 0.2 N H2SO4=Na2CO3 present in 10 mL of mixture
≡5 mL of 0.2 N Na2CO3$
≡0.2×531000×5=0.053 g
Amount of Na2CO3=0.05310×1000=5.3 g/L of mixture
Between first and second end points,
=2.5 mL of 0.2 M H2SO4 used
=2.5 mL of 0.4 N H2SO4 used
=5 mL of 0.2 N H2SO4 used
≡12Na2CO3+NaHCO3 present in 10 mL of mixture
(5−2.5)mL 0.2 N H2SO4
≡NaHCO3 present in 10 mL of mixture
≡2.5 mL 0.2 N NaHCO3
≡0.2×841000×2.5=0.042 g
Amount of NaHCO3=0.04210×1000=4.20g/L of mixture.