Question

Acetic acid, carbonic acid and formic acids are:
A. Strong acids
B. Weak acids
C. (a) and (b) both
D. None of the above

Answer 1

Acids which completely dissociate into their constituent ions when dissolved in water are referred as strong acid and the acids which partially dissociate into their constituent ions are referred as weak acids.

Complete step by step answer:
Acids are defined as those species which on dissolving in water dissociate to give hydrogen ions. The pH of the acid is always less than 7. The strength of the acid can be measured by the extent of its dissociation. The compound which dissolves in water gives more hydrogen ions and is more acidic in nature.
On the basis of their solubility and dissociation in water, the acids are divided into strong acids and weak acids.
Strong acids are those species which in addition to water dissolve completely and dissociate to give its constituent ions. The strong acids are also known as strong electrolyte. Examples of strong acid are HCl, ${H_2}S{O_4}$.
Weak acids are those species which in addition to water does not completely dissolve and dissociates to give its constituent ions. The weak acids are also known as weak electrolyte. Examples of weak acid are acetic acid, formic acid.
Acetic acid, carbonic acid and formic acid all belong to weak acids as they do not completely dissociate into their constituent ions when dissolved in water.
Therefore, the correct option is B.

Note:
Weak acids dissolve in water readily and liberate hydrogen ions but the number of hydrogen ions released per unit volume of the weak acid is lower as compared to the strong acids.