Based on the data given below: \[ \begin{array}{ll} \mathrm{E}_{\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-} / \mathrm{Cr}^{3+}}^{0}=1.33 \mathrm{~V} & \mathrm{E}_{\mathrm{Cl}_{2} / \mathrm{Cl}^{(-)}}^{0}=1.36 \mathrm{~V} \\ \mathrm{E}_{\mathrm{MnO}_{4}^{-} / \mathrm{Mn}^{2+}}^{0}=1.51 \mathrm{~V} & \mathrm{E}_{\mathrm{Cr}^{3+} / \mathrm{Cr}}^{0}=-0.74 \mathrm{~V} \end{array} \] the strongest reducing agent is :

JEE Main · 2025 · 24 Jan 2025 · Shift 2 · Redox Reactions and Electrochemistry

Based on the data given below:

E_{Cr_{2} O_{7}^{2 -} / Cr^{3 +}}^{0} = 1.33 V E_{MnO_{4}^{-} / Mn^{2 +}}^{0} = 1.51 V E_{Cl_{2} / Cl^{(-)}}^{0} = 1.36 V E_{Cr^{3 +} / Cr}^{0} = - 0.74 V

the strongest reducing agent is :

(A) $Mn^{2 +}$
(B)Cr✓ Correct
(C) $MnO_{4}^{-}$
(D) $Cl^{-}$

Answer: (B)

Solution

The strongest reducing agent is the species with the most negative (or least positive) standard reduction potential, since it has the greatest tendency to lose electrons and be oxidized. Among the given couples,

E_{C r^{3 +} /Cr}^{0} = - 0.74 V

is far lower than the others —

C r_{2} O_{7}^{2 -} /C r^{3 +}

C l_{2} /C l^{-}

and

Mn O_{4}^{-} /M n^{2 +}

are all strongly positive, which marks those species as oxidizing agents rather than reducing agents.

Metallic chromium, with the most negative reduction potential, is the strongest reducing agent.

JEE Main · 2025 · 24 Jan 2025 · Shift 2 · Single correct option

Practise more: all JEE Main PYQs on Redox Reactions and Electrochemistry →

JEE Main · 2025 · 24 Jan 2025 · Shift 2 · Redox Reactions and Electrochemistry

Solution

More JEE Main questions on Redox Reactions and Electrochemistry