Question

Calculate the volume strength of `H_(2)O_(2)` solution if `50 mL` of `H_(2)O_(2)` solution is diluted with `50 mL` of `H_(2)O_(2)`. `20 mL` of this diluted solution required `40 mL` of `M//60 K_(2)Cr_(2)O_(7)` solution in presence of `H_(2)O_(2)` for complete reaction.

Answer 1

`underset((n=2))(H_(2)O_(2))-=underset((n=6))(Cr_(2)O_(7)^(2-))`
`mEq-=mEq`
`N_(1)V_(1)-=N_(2)V_(2)`
`N_(1)xx20-=1/60xx6xx40`
`N_(1)=(6xx40)/60=1/20=0.2 N` of `100 mL` of `H_(2)O_(2)` on dilution
The normality of the `50 mL` of `H_(2)O_(2)` should be twice the normality of `20 mL` of the diluted solution of `H_(2)O_(2)`since the volume of `H_(2)O_(2)` solution has doubled.
`(50 mL of H_(2)O_(2)+50 mL of H_(2)O=100 mL` of solution `H_(2)O_(2)`)
`:. N_(1)V_(1)=N_(2)V_(2)`
`0.2xx100mL=N_(2)xx50 mL`
`N_(2)-=0.4 N`
`:.` Volume strength of `H_(2)O_(2)=5.6xx0.4`
`=2.24` volume of `O_(2)`