1 litre solution containing 4.5 milimoles of `Cr_(2)O_(7)^(-)` and 15 milimoles of `Cr^(3+)` shows a `pH` of 2.0.
The potential of the reduction half reaction is approximately `xV`. Then `[x]` is ……… where [ ] is
GIF.`(E^(@)` of `Cr_(2)O_(7)^(2-)//Cr^(3+)` is `1.33V`)

Answer

1

Explanation

`14H^(+)+Cr_(2)O_(7)^(--)+6e^(-)to 2Cr^(3)+7H_(2)O`
`E_(Cr_(2)O_(7)^(-)//Cr^(3+))=1.33+0.059/6"log"_(10)(4.5xx10^(-31))/(2.25xx10^(-4))`
`= 1.33+ 0.059/5 "log"_(10)(2xx10^(-27))`
`=1.06`
`=1V`