List of top Chemistry Questions on Electrochemical Cells

The elements of the 3d transition series are given as: Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn. Answer the following:

Copper has an exceptionally positive \( E^\circ_{\text{M}^{2+}/\text{M}} \) value, why?

Consider the following electrochemical cell at standard condition. $$ \text{Au(s) | QH}_2\text{ | QH}_X(0.01 M) \, \text{| Ag(1M) | Ag(s) } \, E_{\text{cell}} = +0.4V $$ The couple QH/Q represents quinhydrone electrode, the half cell reaction is given below: $$ \text{QH}_2 \rightarrow \text{Q} + 2e^- + 2H^+ \, E^\circ_{\text{QH}/\text{Q}} = +0.7V $$

In the above diagram, the standard electrode potentials are given in volts (over the arrow). The value of \( E^\circ_{\text{FeO}_4^{2-}/\text{Fe}^{2+}} \) is:

Assertion (A): Cu cannot liberate \( H_2 \) on reaction with dilute mineral acids. 
Reason (R): Cu has positive electrode potential.

In a reaction:\( MnO_4^- + 8H^+ + 5e \, \overset{A}⇢ + H_2O\)
A stands for:
In metallurgy the term “gangue” is used for :

E^∘ for the cell, Zn|Zn²+(aq)||Cu²+(aq)|Cu is 1.10V at 25^∘C. The equilibrium constant of the reaction Zn + Cu²+(aq) rightleftharpoons Cu + Zn²+(aq) is of the order of

The equilibrium constant for the disproportionation reaction 2Cu⁺(aq) rightleftharpoons Cu(s) + Cu²+(aq) at 25^∘C (EᶜircCᵤ⁺/Cᵤ=0.52V, EᶜircCᵤ²+/Cᵤ⁺=0.16V) is:
The EMF of the cell Tl|Tl⁺(0.001M)||Cu²+(0.01M)|Cu is 0.83V. The cell EMF can be increased by:
The efficiency of fuel cell is given by the expression η is
The standard electrode potentials are:
\(E^\circ(\text{Zn}^{2+}/\text{Zn}) = -0.76 \, \text{V}, \quad E^\circ(\text{Cu}^{2+}/\text{Cu}) = +0.34 \, \text{V}\).
The equilibrium constant for the reaction
\(\text{Zn} + \text{Cu}^{2+} \rightleftharpoons \text{Cu} + \text{Zn}^{2+}\)
at \(25^\circ \text{C}\) is of the order of
The EMF of the cell
\( \text{Ti} \mid \text{Ti}^+ (0.001\,\text{M}) \; \| \; \text{Cu}^{2+} (0.01\,\text{M}) \mid \text{Cu} \)
is \( 0.83\,\text{V} \).
The cell EMF can be increased by:
The equilibrium constant for the disproportionation reaction
\( 2\text{Cu}^+ (aq) \rightleftharpoons \text{Cu} (s) + \text{Cu}^{2+} (aq) \)
at \( 25^\circ \text{C} \) is given that
\( E^\circ_{\text{Cu}^+/\text{Cu}} = 0.52\,\text{V}, \quad E^\circ_{\text{Cu}^{2+}/\text{Cu}^+} = 0.16\,\text{V} \).
In the cell reaction \(\text{Cu(s)} + 2\text{Ag}^+(\text{aq}) \rightarrow \text{Cu}^{2+}(\text{aq}) + 2\text{Ag(s)}\), \(E^\circ_{\text{cell}} = 0.46\,\text{V}\). By doubling the concentration of \(\text{Cu}^{2+}\), \(E_{\text{cell}}\) is:
Cu\(^+\) is unstable in solution and undergoes simultaneous oxidation and reduction according to the reaction \(2\text{Cu}^+(\text{aq}) \rightarrow \text{Cu}^{2+}(\text{aq}) + \text{Cu(s)}\). Choose the correct \(E^\circ\) for the above reaction if \(E^\circ_{\text{Cu}^{2+}/\text{Cu}} = +0.34\,\text{V}\) and \(E^\circ_{\text{Cu}^+/\text{Cu}} = +0.15\,\text{V}\).
Which of the following will form the cathode with respect to iron an electrode cell?
How many of the given statements are true for fuel cell? 
A. It is a type of Galvanic cell 
B. It is used for providing electrical power in space programmes. 
c. Hydrogen and oxygen are bubbled through porous carbon electrodes into concentrated NaOH solution 
D. It produces electricity with an efficiency of 40% 
E. It is pollution free cell
Identify the change occuring in oxidation state of Mn in cell reaction of dry cell of clock during its use