Question

For an electrochemical reaction occuring in a galvanic cell.
$2{Fe}_{\left(aq\right)}^{+3}+{Zn}_{\left(s\right)}\to {Zn}_{\left(aq\right)}^{+2}+2{Fe}_{\left(aq\right)}^{+2}$
if concentration of ${Fe}^{+2}$ is increased.

• A. $E_{cell}$ will remain unchanged
• B. $E_{cell}$ will decrease
• C. $pH$ of the solution will change
• D. less non P-V work will be obtained

Answer 1

The correct option is B $E_{cell}$ will decrease

In given cell reaction we have,

at anode $Zn\to Z{n}^{2+}+2e^{-}$

at cathode $2F{e}^{3+}+2e^{-}\to 2F{e}^{+2}$

$E_{cell}=E_{cell}^0$ -$\frac{0.0591}{2}$ $log$$\frac{Z{n}^{2+}(F{e}^{2+}{)}^2}{(F{e}^{3+}{)}^2}$

so, on increasing the concentration of $F{e}^{2+}$ions

$E_{cell}$ will decreases.