Question

Which of the following are weak acids?

• A. ${\text{H}}_2{\text{SO}}_4$
• B. ${\text{CH}}_3\text{COOH}$
• C. $\text{HCOOH}$
• D. $\text{HCl}$

Answer 1

Answer: (B), (C)

The correct options are
B ${\text{CH}}_3\text{COOH}$
C $\text{HCOOH}$

The strength of an acid depends on how easily it can dissociate in an aqueous solution and release ${\text{H}}^{+}$ ions. Organic acids obtained from natural sources are usually weak acids because they do not dissociate quickly to release ${\text{H}}^{+}$ ions.

Therefore, acetic acid $\left({\text{CH}}_3\text{COOH}\right)$ and formic acid $\left(\text{HCOOH}\right)$ are weak acids because they cannot give ${\text{H}}^{+}$ ions easily.

Mineral acids like hydrochloric acid $\left(\text{HCl}\right)$ and sulphuric acid $\left({\text{H}}_2{\text{SO}}_4\right)$ are strong acids as they dissociate easily to release ${\text{H}}^{+}$ ions.