Question

In the equation, $NaOH + HN{O_3} \to NaN{O_3} + {H_2}O$, nitric acid is:
A) An oxidising agent
B) An acid
C) A nitrating agent
D) A dehydrating agent

Answer 1

Hint: Observe the reaction carefully which shows the exchange of the atoms and groups in the reaction. The nitric acid in the reaction loses an atom and forms another molecule and one can analyze this behavior and relate them with the chemical concepts given in the option.

Complete step by step answer:
1) First of all let's see what happens in the given reaction, the sodium hydroxide when reacted with the nitric acid it produces the sodium nitrate and water.
2) Here in the above reaction the reactant molecule sodium hydroxide ${\text{(NaOH)}}$ loses a hydroxide group i.e. $^ - {\text{OH}}$ and the nitric acid $(HN{O_3})$ loses a hydrogen atom that is proton and both forms a complex that is sodium nitrate.
3) In the above reaction the sodium hydroxide acts as a base that accepts the proton from the nitric acid and the nitric acid acts as acid as it donates the hydrogen atom that is proton to the sodium hydroxide.
4) Hence, the nitric acid acts as an acid in the given reaction as it contributes to the donation of a proton that is a hydrogen atom which shows option B as a correct choice of answer.
Thus option B is the correct answer.


Note:
As there is the formation of the water molecule in the product along with the sodium nitrate which is a salt that means the reaction is of the acid base neutralization type reaction. In any kind of acid base type of reaction, there is always the formation of water molecules and salt molecules which conceptually neutralize each other hence reaction called a neutralization reaction.