Q.

Find the emf of the cell in which the following reaction takes place at 298 K

Ni(s)+2Ag+(0.001M)Ni2+(0.001M)+2Ag(s)

Given that Ecell=10.5 V, 2.303RTF=0.059at 298 K                       [2022]

1 1.0385 V  
2 1.385 V  
3 0.9615 V  
4 1.05 V  

Ans.

(3)

According to Nernst equation,  

E=Ecell-0.059nlog[Ni2+][Ag+]2

Ecell=1.05  (Given)

Note : Please read 10.5 as 1.05 in question.  

E=1.05-0.0592log0.001(0.001)2

=1.05-0.0592log103 =1.05-0.059×32

=1.05-0.0885=0.9615 V