Question

If amixture of `Na_(2)CO_(3)` and NaOH in equimolar quantities when reacts with 0.1 M HCl in presence of phenolphthalein indicator consumes 30 ml of the acid. What will be the volume (in mL) of 0.15 M `H_(2)SO_(4)` used in the separate titration of same mixture in presence of methyl orange indicator.

Answer 1

Correct Answer - 15
In presence of Hph indicator
m. eq. of HCl = m. eq. of `Na_(2)CO_(3)+` m.eq. of NaOH
`30xx0.1=(axx1)+(axx1)`
`:. A=1.5`
In presence of MeOH indicator
m.eq. of `H_(2)SO_(4)`=m.eq. of `Na_(2)CO_(3)` + m. eq. of NaOH
`0.15xx2xxV=(axx2)+(axx1)`
V=15 ml