Question

Identify the type of reaction: $HCl + NaOH{\text{ gives }}NaCl + {H_2}O$ .

Answer 1

The reactants of the given reaction are $HCl$ (hydrochloric acid) and $NaOH{\text{ }}$(sodium hydroxide).Sodium hydroxide is a hydroxide of an alkali metal and is strongly basic in nature and $HCl$ is an equally strong acid.

Complete answer:
A chemical reaction is a process that takes place between one or more chemical species that undo an irreversible chemical change (called the reactants) and lead to the formation of new chemical species with the same set of atoms but different chemical properties (called the products).
There are different types of chemical reactions that can be classified on the basis of the kinds of reactants involved and the type of product obtained along with the liberation of a gas in some cases. If the classification is based upon the reactants and products then the given reaction is an acid-base reaction that gives salt sodium chloride along with water. This is therefore a neutralization reaction. The salt formation is a characteristic of the neutralization reaction.
$HCl(aq) + NaOH(aq) \to NaCl(aq) + {H_2}O(l)$
If the classification is based upon energy differences of the reactants and the products then the reactions can be classified as exothermic or endothermic reactions. In exothermic reactions, heat is evolved and is on the product side and in an endothermic reaction, heat is absorbed and is on the reactants side.
An acid-base reaction evolves a large amount of heat and is therefore an exothermic reaction.
Thus, the given reaction can be identified as a neutralization and exothermic reaction.

Note:
The completion of neutralization can be detected using simple indicators like litmus paper. Both red and blue litmus paper would not undergo any change in colour when dipped in the reaction mixture of an acid-base reaction when it is complete. An exothermic reaction can be identified by measuring the change in the temperature of the reaction medium on completion.