Copper is added to a solution of nitric acid. The solution becomes hot and changes from colorless to dark blue. What is the best explanation for the change in temperature?

When copper is added to a solution of nitric acid, their chemical reaction produces heat.

Explanation:

During the reaction between copper an d nitric acid, the copper metal is oxidised to form copper (ii) ion, by nitrate ion. Then this is converted into notrogen oxide gas. As, a result of this conversion, there is a binding of copper (ii) ion with water molecules of number 6. As a result of this, the copper metal will turn into a solution which is blue and a gas of brown color is obtained.

Thus when copper is added to nitric aci, there is a change in the temperature. The chemical reaction that takes place between Copper and Nitric acid solution generates heat. This process is an exotermic.