Question

What type of reaction involves the breakdown of a molecule by the addition of water?

Answer 1

In the question, we need to break the molecule and we know that a reaction in which a compound breaks down into two or more simpler substances as the product is known as a decomposition reaction. It is also referred to as chemical decomposition of a molecule.

Complete answer:
Double decomposition reaction: It is a type of decomposition reaction in which two constituent reactants interchange the positive and negative ions to form new compounds. Now, as per question, it is clear that the reaction is the type of decomposition reaction because of the breaking down of molecules, but the reaction is proceeding in the presence of water, thus this reaction is known as hydrolysis reaction.
Hydrolysis reaction is a type of double decomposition reaction which consists of water molecules as one of the major products. It is the reversible reaction and can be generally represented as follows:
$AB+{{H}_{2}}O\rightleftharpoons AH+BOH$
There are several types of hydrolysis reactions which are as follows:
1. Salts: This is the most common type of hydrolysis reaction that refers to the reaction of salt with water which involves the interaction between cations or anions of salts and water.
2. Acid-Base: The water molecule in this case acts as a base to give hydroxyl ion to react with acidic carbon like carbon of carbonyl to form products which consist of carboxylic acid groups.
3. ATP: Most of the biochemical reactions which occur in living organisms are in the form of ATP hydrolysis which takes place in the presence of enzymes. The catalytic action of enzymes allows the hydrolysis of molecules like proteins, lipids, fats, etc.
Thus, we can conclude that the breakdown of a molecule by the addition of water is the hydrolysis reaction which is a type of double decomposition reaction.

Note:
Ensure to not to get confused between the term hydrolysis and hydration. Hydrolysis is a type of a double decomposition reaction in which water is present as one of the reactants whereas hydration is a chemical process in which water molecules combine with dehydrated molecules to form hydrated compounds.