Final answer:
In a galvanic cell, a spontaneous chemical reaction occurs to generate electrical energy, unlike in an electrolytic cell where a nonspontaneous reaction is driven by external electrical energy.
Step-by-step explanation:
The type of chemical reaction that occurs in a galvanic cell is a spontaneous reaction. A galvanic cell, also known as a voltaic cell, transforms the energy released from a spontaneous redox reaction into electrical energy.
This is in contrast to an electrolytic cell, where electrical energy from an external source is required to drive a nonspontaneous reaction. The oxidation-reduction reactions in a galvanic cell typically occur in separate compartments that are connected by an external electrical circuit.