What is the voltage of the cell represented at Zn(s)/ Zn\(^{2+}\)(aq) //Cu\(^{2+}\)(aq) /Cu(s) given that...

WAEC 1989

What is the voltage of the cell represented at Zn(s)/ Zn\(^{2+}\)(aq) //Cu\(^{2+}\)(aq) /Cu(s) given that for Cu\(^{2+}\)(aq)/ Cu (s) E\(^0\) = 0.337V and for Zn\(^{2+}\)(aq) /Zn(s)' E\(^0\) = - 0.763V?

A. +0.426V
B. -0.426V
C. -0.337V
D. -1.10V
E. +1.10V

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Correct Answer: Option E

Explanation

To calculate the voltage of a cell with Zn and Cu, you use the standard cell potential formula: E°cell = E°cathode - E°anode.

Identifying the Half-Reactions:
- Oxidation: Zn(s) → Zn\(^{2+}\)(aq) + 2e- (Anode)
- Reduction: Cu\(^{2+}\)(aq) + 2e- → Cu(s) (Cathode)
Standard Reduction Potentials:
- Cu\(^{2+}\)(aq) + 2e- → Cu(s): E° = +0.337 V
- Zn\(^{2+}\)(aq) + 2e- → Zn(s): E° = -0.763 V
Calculating the Standard Cell Potential (E°cell):
- E°cell = E°cathode - E°anode
- E°cell = (+0.337 V) - (-0.763 V)
- E°cell = + 1.10 V