The exothermic step in the dissolution of NaCl in water is
A)the separation of the ions in the salt.
B)the separation of the water molecules.
C)solvation (hydration)of the ions from the salt.
D)separation of the ions in the salt and the separation of the water molecules.

Question

Quizplus · Accepted Answer

The exothermic step in the dissolution of NaCl in water is the solvation (hydration) of the ions from the salt. This is because when NaCl is added to water, the polar water molecules surround the positive and negative ions of NaCl and form a shell around them. This releases energy in the form of heat, making the process exothermic. The separation of the ions in the salt and the separation of the water molecules are both endothermic steps, as they require energy to break the interactions between the ions and between the water molecules. Therefore, option C is the correct answer.

The Exothermic Step in the Dissolution of NaCl in Water