Question

The oxidation potential values of $A,B,C$ and $D$ are $-0.03V,+0.108V,-0.07V$ and $+0.1V$ respectively. The non-spontaneous cell reaction takes place between them:

• A. $A$ and $B$
• B. $B$ and $D$
• C. $D$ and $A$
• D. $B$ and $C$

Answer 1

The correct option is A $A$ and $B$

(i) The electrode with higher oxidation potential acts as anode and electrode with lower oxidation potential acts as cathode.
(ii) Cell reaction is spontaneous when $E_{cell}$ is positive. $(E_{cell}=E_C-E_A)$
Given, oxidation potential of $A=-0.03V$ oxidation potential of $B=+0.108V$
oxidation potential of $C=-0.07V$
oxidaton potential of $D=+0.1V$
(a) A and B, oxidation potential of $A=-0.03$
Oxidation potential of $B=+0.108$
$\because$ Oxidation potential of $B$ is more than $A$,
$\therefore$ Oxidation of $A$ is not possible.
$\therefore$ This cell having $A$ as anode and $B$ as cathode is not possible.
(b) $B$ and $D$, oxidation potential of $B=0.108V$ oxidation potential of $D=+0.1V$
$\because$ Oxidation potential of $B$ is more than $D$.
$\therefore$ Oxidation of $B$ is possible and cell reaction is feasible.
(c) $D$ and $A$, oxidation potential of $D=0.1V$
Oxidation potential of $A=-0.03V$
$\because$ Oxidation potential of $D$ is more than $A$.
$\therefore$ Cell will work with $D$ as anode and $A$ as cathode.
(d) $B$ and $C$, oxidation potential of $B=0.108V$
Oxidation potential of $C=-0.07V$
$\because$ Oxidation potential of $B$ is more than $C$.
$\therefore$ Cell will work with $B$ as anode and $C$ as cathode.
$\therefore$ The non-spontaneous cell reaction takes place between $A$ and $B$.