1.325 g of anhydrous sodium carbonate are dissolved in water and the solution made up to 250 mL. On titration 25 mL of this solution neutralise 20 mL of a solution of suphuric acid. How much water should be added to 450 mL of this acid solution to make it exactly N//12 ?

1.325 g of anhydrous sodium carbonate are dissolved in water and the s

1.	1.325 g of anhydrous sodium carbonate are dissolved in water and the solution made up to 250 mL. On titration 25 mL of this solution neutralise 20 mL of a solution of suphuric acid. How much water should be added to 450 mL of this acid solution to make it exactly N//12 ?
Answer» Solution :EQ. mass of `Na_(2)CO_(3)=("Mol.mass")/(2)=(106)/(2)=53` 250 mL of the SODIUM carbonate solution contains = 1.325 g 1000 mL of the sodium carbonate solution contains `=(1.325g)/(250)xx1000=5.300` g NORMALITY of `Na_(2)CO_(3)` solution` =("Strength "(g//L))/("Eq. mass")` `=(5.30)/(53)=(1)/(10)N` Applying `UNDERSET((Na_(2)CO_(3)))(N_(1)V_(1))-=underset((H_(2)SO_(4)))(N_(2)V_(2))` `(1)/(10)xx25=N_(2)xx20` `N_(2)=(25)/(10xx20)=(1)/(8)` Applying`underset(("Before dilution"))(N_(B)V_(B))-=underset(("After dilution"))(N_(A)V_(A))` `=(1)/(8)xx450=(1)/(12)xxV_(A)` `V_(A)=(450xx12)/(8)=675 mL` Water to be added for dilution =(675-450)=225 mL