MnO_4^- (aq) + 8H^+ (aq) + 5e^- to Mn^{2+} (a | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(A) The given half-reactions are:$(1) MnO_4^- + 8H^+ + 5e^- 	o Mn^{2+} + 4H_2O$; $\Delta G_1^o = -n_1 F E_1^o = -5 	imes F 	imes 1.51 = -7.55 F$$(2

Vedclass · Accepted Answer

$1.71$

Vedclass · Answer

(A) The given half-reactions are:$(1) MnO_4^- + 8H^+ + 5e^- 	o Mn^{2+} + 4H_2O$; $\Delta G_1^o = -n_1 F E_1^o = -5 	imes F 	imes 1.51 = -7.55 F$$(2) MnO_2 + 4H^+ + 2e^- 	o Mn^{2+} + 2H_2O$; $\Delta G_2^o = -n_2 F E_2^o = -2 	imes F 	imes 1.21 = -2.42 F$We need the reaction: $MnO_4^- + 4H^+ + 3e^- 	o MnO_2 + 2H_2O$This can be obtained by subtracting reaction $(2)$ from reaction $(1)$:$(1) - (2): (MnO_4^- + 8H^+ + 5e^-) - (MnO_2 + 4H^+ + 2e^-) 	o (Mn^{2+} + 4H_2O) - (Mn^{2+} + 2H_2O)$$MnO_4^- + 4H^+ + 3e^- 	o MnO_2 + 2H_2O$The change in Gibbs free energy is $\Delta G_3^o = \Delta G_1^o - \Delta G_2^o = -7.55 F - (-2.42 F) = -5.13 F$Since $\Delta G_3^o = -n_3 F E_3^o$ and $n_3 = 3$,we have:$-3 F E_3^o = -5.13 F$$E_3^o = \frac{5.13}{3} = 1.71 \ V$

$MnO_4^- (aq) + 8H^+ (aq) + 5e^- \to Mn^{2+} (aq) + 4H_2O (l)$; $E_1^o = 1.51 \ V$
$MnO_2 (s) + 4H^+ (aq) + 2e^- \to Mn^{2+} (aq) + 2H_2O (l)$; $E_2^o = 1.21 \ V$
$MnO_4^- (aq) + 4H^+ (aq) + 3e^- \to MnO_2 (s) + 2H_2O (l)$; $E_3^o = ?$
Value of $E_3^o$ will be ............ $V$

Similar Questions

The $E^o$ values of $Mg^{2+}/Mg$ is $-2.37 \ V$,$Zn^{2+}/Zn$ is $-0.76 \ V$,and $Fe^{2+}/Fe$ is $-0.44 \ V$. Which of the following statements is correct?

$A$ standard hydrogen electrode has zero electrode potential because

Which of the following metals will not evolve $H_2$ gas from dilute $H_2SO_4$ solution?

$A$ galvanic cell consists of a copper electrode and a standard hydrogen electrode. If $E^0_{(Cu^{2+}(aq)|Cu(s))} = +0.34 \text{ V}$, identify the reaction taking place at the positive electrode during the working of the cell.

Amongst the following electrodes,the one with zero electrode potential is

Vedclass Test Series

Exam Paper Generator

Online Exam Module

$MnO_4^- (aq) + 8H^+ (aq) + 5e^- \to Mn^{2+} (aq) + 4H_2O (l)$; $E_1^o = 1.51 \ V$$MnO_2 (s) + 4H^+ (aq) + 2e^- \to Mn^{2+} (aq) + 2H_2O (l)$; $E_2^o = 1.21 \ V$$MnO_4^- (aq) + 4H^+ (aq) + 3e^- \to MnO_2 (s) + 2H_2O (l)$; $E_3^o = ?$Value of $E_3^o$ will be ............ $V$