During a lab activity, students prepared two solutions separately at the same temperature. later they mixed the solutions and the temperature dropped. why? there was no energy input during the chemical reaction. energy was absorbed during the chemical reaction. energy was released during the chemical reaction. the temperature of the surroundings dropped.

Energy was absorbed during the chemical reaction.

Explanation:

When the temperature of a reaction mixture drops, then the reaction is endothermic. Heat was absorbed by the reaction mixture leading to a drop in temperature.

This drop in temperature tells us that the energy of reactants is greater than the energy of products in the reaction hence ∆H is positive.