Q.

Consider the cell

Pt(s)|H2(g,1 atm)H+(aq, 1 M)Fe3+(aq).Fe2+(aq)|Pt(s)

When the potential of the cell is 0.712 V at 298 K, the ratio [Fe2+][Fe3+] is ______ (Nearest Integer).

Given: Fe3++e-=Fe2+,  E0Fe3+,Fe2+|Pt=0.771

2.303RTF=0.06 V                                  [2023]


Ans.

(10)

Anode12H2(g)H+(aq)+e-

CathodeFe3++e-Fe2+

Overall: 12H2+Fe3+n=1H++Fe2+

Ecell=Ecell-0.0591log[Fe2+][Fe3+]×[H+][PH2]1/2

0.712=0.771-0.059 log[Fe2+][Fe3+]

log[Fe2+][Fe3+]=1

So [Fe2+][Fe3+]=10