KCI is a metal halide salt composed of potassium and chloride. It is odorless, and it has a white or colorless crystal appearance. The solid salt dissolves in water. When a flask filled with water has potassium chloride added to it, this is an endothermic reaction or endothermic process.
In this process, endothermic reactions or reactors absorb energy from its surroundings. The energy this type of reaction absorbs is usually, (but not always) heat. As the process absorbs heat from its surroundings, the water will get colder. Melting an ice cube would be an example where the melting process absorbs heat from its surroundings.