0.4 g of a mixutre containing sodium oxalate `(Na_2C_2O_4)` and potassium oxalate requires 50 " mL of " `(M)/(60)K_2Cr_2O_7` solution in acidic medium for complete reaction. Calculate the percentage composition of the mixture.

Explanation

`Ew(Na_2C_2O_4)=(2xx23+2xx12+4xx16)/(2)=(134)/(2)=67g`
`Ew(K_2C_2O_4)=(2xx39+2xx12+4xx16)/(2)=(166)/(2)=83g`
Let x g of `Na_2C_2O_4` and `(0.4-x)g of K_2Cr_2O_7`
`((x)/(67)+(0.4-x)/(83))xx10^(3)=50xx(1)/(60)xx6` (n-factor)
`83x+67(0.4-x)=(5xx67xx83)/(10^(3))`
`16x=27.8-67xx0.4`
`=27.8-26.8=1.0`
`x=(1)/(16)=0.06g`
`% of Na_2C_2O_4=(0.06xx100)/(0.4)=15.6%`
`% of K_2C_2O_4=100-15.6=84.4%`