In which type of reaction is heat released into the surroundings?

The response identifies exothermic reactions as the type of reaction where heat is released into the surroundings. This is correct because, during an exothermic reaction, the products formed have lower energy than the reactants. As the reactants convert into products, the excess energy is released, often in the form of heat. This release of energy can cause the temperature of the surrounding environment to increase.

In contrast, endothermic reactions absorb energy, resulting in a decrease in the temperature of the surroundings. Neutralization reactions can be either exothermic or endothermic depending on the reactants used, but they are not exclusively defined by the release of heat. Redox reactions involve the transfer of electrons and can also be either exothermic or endothermic, but again, they do not specifically denote a release of heat. Therefore, exothermic reactions are the direct answer for the condition described in the question.