What type of reaction occurs when a client feels heat during a gel nail service?

The correct answer is exothermic. During a gel nail service, a chemical reaction occurs when the gel is cured under a UV lamp. This curing process generates heat, which is characteristic of an exothermic reaction. In an exothermic reaction, energy is released to the surroundings, often in the form of heat, resulting in the client feeling warmth during the application.

Understanding the nature of this reaction is important because gel nails rely on this heat to properly polymerize and set the gel material, ensuring a durable and long-lasting finish. Recognizing that the warmth is a normal part of the process helps technicians manage client comfort and expectations during the service.

The other options relate to types of thermal processes, but exothermic specifically highlights the release of heat resulting from the chemical changes happening during the curing of gel nails.