Question

Assertion: ${H_2}C{O_3}$ is a strong acid.

Reason: A strong acid dissociates completely or almost completely in water.

A. Both assertion and reason are correct and reason is the correct explanation for assertion.

B. Both assertion and reason are correct but reason is not the correct explanation for assertion.

C. Assertion is not correct but reason is correct.

D. Both assertion and reason are incorrect.

Answer 1

To know whether ${H_2}C{O_3}$ comes under the category of strong acid we must first know what a strong acid is. The strength of an acid is determined from the ease with which the acid loses a proton. A strong acid is said to ionize completely in an aqueous solution by losing one proton. Strong acids are used in catalyzing reactions which includes the synthesis and hydrolysis of carbonyl compounds.

Complete step-by-step answer:

${H_2}C{O_3}$ is not a strong acid. It is a weak acid. ${H_2}C{O_3}$ dissociates into a proton and a bicarbonate ion. This compound only partly dissociates in aqueous solutions. Further we can say that the conjugate base of carbonic acid, which is the bicarbonate ion, is a relatively good base. These are the reasons why we classify carbonic acid as a weak acid and not as a strong acid.

A strong acid dissociates completely or almost completely in water. Any acid that dissociates hundred percent into ions is said to be a strong acid and acids which do not dissociate completely into ions are weak acids.

Hence we can say that the correct option is C which states that the Assertion is not correct but reason is correct.

Note: Total of seven acids can be considered as strong acids in the field of chemistry which are, hydrochloric acid, hydrobromic acid, hydroiodic acid or hydriodic acid, sulfuric acid, nitric acid, chloric acid, perchloric acid. These acids are categorized as strong acids because they almost completely dissociate into their constituent ions, which includes their anionic conjugate base and a proton when they are dissolved in water.