Neco 2020 Chemistry Question 25

Practice objective / multiple choice question 25 from the 2020 Neco Chemistry examination.

Neco 2020 Chemistry Objective / Multiple Choice Medium Difficulty
Question 25 NECO • 2020 • CHEMISTRY • objective

Consider a galvanic cell: \( \mathrm{Zn|Zn^{2+}(0.010\;M) || Cu^{2+}(0.10\;M)|Cu} \). Standard electrode potentials are \( E^\circ_{\mathrm{Zn^{2+}/Zn}} = -0.76\;\text{V} \) and \( E^\circ_{\mathrm{Cu^{2+}/Cu}} = +0.34\;\text{V} \). (a) Calculate the cell potential at 25 °C. (b) If the concentrations are reversed (\( \mathrm{Zn^{2+}} = 0.10\;M, \mathrm{Cu^{2+}} = 0.010\;M \)), determine the cell potential and state whether the direction of the spontaneous reaction changes.

Answer Options

A. E = 0.98 V; with reversed concentrations E = 0.92 V and the reaction remains spontaneous but in the opposite direction (Cu oxidises, Zn²⁺ reduces).
Correct Answer B. E = 1.13 V; with reversed concentrations E = 1.07 V and the reaction remains spontaneous in the same direction (Zn oxidises, Cu²⁺ reduces).
C. E = 1.10 V; with reversed concentrations E = 1.05 V and the reaction remains spontaneous in the same direction (Zn oxidises, Cu²⁺ reduces).
D. E = 1.13 V; with reversed concentrations E = 0.95 V and the reaction becomes non‑spontaneous (Cu oxidises, Zn²⁺ reduces).
Correct Answer
B
Correct Option:
E = 1.13 V; with reversed concentrations E = 1.07 V and the reaction remains spontaneous in the same direction (Zn oxidises, Cu²⁺ reduces).

About This Question

This is Neco 2020 Chemistry Question 25. It is one of the objective questions from the 2020 Neco Chemistry examination.

Difficulty level: Medium .

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