Question

80 " mL of " `KMnO_4` solution reacts with 3.4 g of `Na_2C_2O_4.2H_2O` in acidic medium. The molarity of the `KMnO_4` solution is.
(a). 0.5M
(b). 0.1M
(c). 5M
(d). 1M

Answer 1

(b). `Mw[Na_2C_2O_4.2H_2O]`
`=2xx23+2xx12+4xx16+2xx18=170g`
`[5e^(-)+MnO_4^(ɵ)toMn^(2+)](n=5)`
`[C_2O_4^(2-)to2CO_2+2e^(-)](n=2)`
`MnO_4^(ɵ)-=C_2O_4^(2-)`
`1mEq-=1mEq`
`80xxN-=(wxx10^(3))/(Ew)mEq=(3.4xx10^(3))/((170)/(2))`
`N(MnO_4^(ɵ))-=(3.4xx10^(3))/((170)/(2)xx80)=0.5N`
`M(MnO_4^(ɵ))-=(0.5N)/(5)=0.1`M