Question #544e6

1 Answer
May 2, 2016

0.954g

Explanation:

Here 200mL0.5M HCl contaims
2000.51000=0.1mole HCl
=0.1gmequivalent HCl

25mLpartly neutralised HCl requires 20.5mL 0.5M NaOH .
forcomlere neutralisation

200mLpartly neutralised HCl requires 20.520025=164mL 0.5M NaOH for complete neutralisation

164mL0.5M NaOH solution contains
1640.51000=.082mole or gm-equivalent NaOH.

Let the mass of Na2CO3added be x g or x53gm-equivalent
where equivalent mass ofNa2CO3=53
Here total no.of gm-equivalent of base =total no.of gm-equivalent
of acid

x53+0.082=0.1

x=0.01853=0.954g