Chemistry Regents Practice Test

What type of energy conversion occurs in an operating electrolytic cell?

1. Electrical energy to chemical energy

2. Nuclear energy to thermal energy

3. Thermal energy to mechanical energy

4. Chemical energy to electrical energy

The correct answer is: Nuclear energy to thermal energy

An operating electrolytic cell primarily converts electrical energy into chemical energy. In the process, electrical energy is supplied to the cell, which drives a non-spontaneous chemical reaction to occur. This is seen when an electric current is passed through an electrolyte, causing chemical reactions to take place at the electrodes—resulting in the decomposition of compounds or the deposition of materials. The other choices do not apply in this context: nuclear energy to thermal energy involves nuclear reactions while thermal energy to mechanical energy typically describes heat engines. Chemical energy to electrical energy is a description of galvanic cells or batteries, where spontaneous reactions generate electrical energy. However, in an electrolytic cell, it is the conversion of electrical energy into chemical energy that is fundamental to its operation.