Four metals A, B, C and D have standard electrode potentials of −3.05 V, −1.66 V, −0.40 V and +0.80 V, respectively. Which of them is the strongest reducing agent?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → A
A standard electrode potential is a reduction potential. The lower (more negative) it is, the less the metal ion tends to be reduced and the more readily the metal gives up electrons, so the metal is a stronger reducing agent.
Ordering the four metals by E°: A (−3.05 V) < B (−1.66 V) < C (−0.40 V) < D (+0.80 V). A has the most negative E°, so A is the strongest reducing agent and D the weakest.
NCERT (2026-27 edition):
2.2.1 Measurement of Electrode Potential – “… Lithium has the lowest electrode potential indicating that lithium ion is the weakest oxidising agent while lithium metal is the most powerful reducing agent in an aqueous solution.”