An electrochemical cell is constructed using two half-cells: Al (s) in Al (NO2) 3 (aq) and Cu (s) in Cu (NO3) 2 (aq). The two half cells are connected by a KNO3 salt bridge and two copper wires from the electrodes to a voltmeter. Based on their respective standard reduction potentials, which half-cell is the cathode?

Question

Chemistry

Stephanie Bonilla

9 March, 16:27

An electrochemical cell is constructed using two half-cells: Al (s) in Al (NO2) 3 (aq) and Cu (s) in Cu (NO3) 2 (aq). The two half cells are connected by a KNO3 salt bridge and two copper wires from the electrodes to a voltmeter. Based on their respective standard reduction potentials, which half-cell is the cathode?

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Answers (1)

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Chuckles · Answer 1

Cu (s) in Cu (NO₃) ₂ (aq)

Explanation:

The standard reduction potential (E°) is the energy necessary to reduce the atom in a redox reaction. When an atom reduces it gains electrons from other than oxides. As higher is E°, easily it will reduce. The substance that reduces is at the cathode of a cell, where the electrons go to, and the other that oxides are at the anode of the cell.

The standard reduction potentials from Al (s) and Cu (s) are, respectively, - 1.66V and + 0.15V, so the half-cell of Cu (s) in Cu (NO₃) ₂ (aq) is the cathode.