Question

`4.0 g` of a mixture of `Nacl` and `Na_(2) CO_(3)` was dissolved in water and volume made up to `250 mL`. `25 mL` of this solution required `50 mL` of `N//10 HCl` for complete neutralisation. Calculate the percentage composition of the original mixture.

Answer 1

Correct Answer - B
`NaCl` does not react with `HCl`
`NaCO_(3) + 2HCl rarr 2NaCl + H_(2)O + CO_(2)`
mEq of `Na_(2)CO_(3) -= mEq "of" HCl`
`-= 50 xx (1)/(10) = 5` mEq per `25 mL`
`-= 50 mEq` per `250 mL`
Weight of `Na_(2)CO_(3) = 50 xx 10^(-3) xx (106)/(2) = 2.65 g`
% of `Na_(2)CO_(3) = (2.65)/(4.0) xx 100 = 66.25%`