The correct value of cell potential in volt for the reaction that occurs when the following two half cells are connected, is:
$$\mathrm{Fe}_{\text {(aq) }}^{2+}+2 \mathrm{e}^{-} \rightarrow \mathrm{Fe}(\mathrm{s}), \mathrm{E}^{\circ}=-0.44 \mathrm{~V}$$
$$\mathrm{Cr}_2 \mathrm{O}_7^{2-}{ }_{\text {(aq) }}+14 \mathrm{H}^{+}+6 e^{-} \rightarrow 2 \mathrm{Cr}^{3+}+7 \mathrm{H}_2 \mathrm{O},$$
$$\mathrm{E}^{\circ}=+1.33 \mathrm{~V}$$
 1 +1.77 V 2 +2.65 V 3 +0.01 V 4 +0.89 V
Subtopic:  Electrode & Electrode Potential |
72%
From NCERT
NEET - 2023
Hints

Given below are half-cell reactions:
$$\mathrm{MnO}_{4}^{-}+8 \mathrm{H}^{+}+5 \mathrm{e}^{-} \rightarrow \mathrm{Mn}^{2+}+4 \mathrm{H}_{2} \mathrm{O},$$
$$\mathrm{E}_{\mathrm{Mn}^{2+}}^{\circ} / \mathrm{MnO}_{4}^{-}=-1.510 \mathrm{~V}$$
$$\frac{1}{2} \mathrm{O}_{2}+2 \mathrm{H}^{+}+2 \mathrm{e}^{-} \rightarrow \mathrm{H}_{2} \mathrm{O},$$
$$\mathrm{E}_{\mathrm{O}_{2} / \mathrm{H}_{2} \mathrm{O}}^{\circ}=+1.223 \mathrm{~V}$$
Will the permanganate ion, $$\mathrm{MnO}_{4}^{-}$$ , liberate $$\mathrm{O}_{2}$$ from water in the presence of an acid?

1. No, because $$\mathrm{E}_{\text {cell }}^{\circ}=-2.733 \mathrm{~V}$$
2. Yes, because $$\mathrm{E}_{\text {cell }}^{\circ}=+0.287 \mathrm{~V}$$
3. No, because $$\mathrm{E}_{\text {cell }}^{\circ}=-0.287 \mathrm{~V}$$
4. Yes, because $$\mathrm{E}_{\text {cell }}^{\circ}=+2.733 \mathrm{~V}$$
Subtopic:  Electrode & Electrode Potential |
From NCERT
NEET - 2022
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

Two half cell reactions are given below:
\begin{aligned} &\mathrm{Co}^{3+}+e^{-} \rightarrow \mathrm{Co}^{2+}, \mathrm{E}_{\mathrm{Co}^{2+} / \mathrm{Co}^{3+}}^{\circ}=-1.81 \mathrm{~V} \\ &2 \mathrm{Al}^{3+}+6 e^{-} \rightarrow 2 \mathrm{Al}(\mathrm{s}), \mathrm{E}_{\mathrm{Al} / \mathrm{Al}^{3+}}^{\circ}=+1.66 \mathrm{~V} \end{aligned}
The standard EMF of a cell with feasible redox reaction will be:

 1 +7.09 V 2 +0.15 V 3 +3.47 V 4 –3.47 V
Subtopic:  Electrode & Electrode Potential |
64%
From NCERT
NEET - 2022
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh