A half cell is prepared by `K_(2)Cr_(2)O_(7)` in a buffer solution of `pH =1`. Concentration of `K_(2)Cr_(2)O_(7)` is `1M`. To 3 litre of this solution `570 gm` of `SnCI_(2)` is added which is oxidised completely to `SnCI_(4)`.
Given: `E_(Cr_(2)O_(7)^(-2)//Cr^(+3).H^(+))^(@) = 1.33V, (2.303)/(F) RT = 0.06`,
Atomic of mass `Sn = 119, E_(Sn^(+4)//Sn^(+2))^(@) = 0.15`
Emf of the cell `Pt|underset((0.1M))(Sn^(+2)),underset((0.2M))(Sn^(+4)),underset((1M))(H^(+)):||:underset((0.2M))(Cr_(2)O_(7)^(2-)),underset((1M))(Cr^(+3)),underset((1M))(H^(+)):|:Pt`

Options

A. `-1.18V`
B. `1.176 V`
C. `1.18 V`
D. None of these

Answer

B

Explanation

`Cr_(2)O_(6)^(-2)+3Sn^(+2)+14H^(+)rarr 3sn^(+4)+2Cr^(+3)+7H_(2)O`
`E^(@)=1.18`
`E=1.18-(0.059)/(6)"log"((0.2)^(3)(1)^(2))/((0.2)(0.1)^(3)(1)^(14))`