If the temperature of the surroundings decreases, it means that heat is being absorbed from the surroundings by the substance and water. This means that the process is endothermic.
When a substance dissolves in water and the temperature of the surroundings decreases, it indicates an endothermic process. In an endothermic process, energy is absorbed from the surroundings, resulting in a decrease in temperature. Therefore, in this case, the dissolution of the substance in water is an endothermic process.
