Question

Which of the following acid is a weak acid?

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

Answer 1

The correct option is A

${\mathrm{CH}}_3\mathrm{COOH}$

Explanation for the correct option:

(A) ${\mathrm{CH}}_3\mathrm{COOH}$

• A weak acid only partially ionizes in water and creates a little number of hydrogen ions.
• Whereas a strong acid totally ionizes in water to produce a significant amount of hydrogen ions.
• Since just, a very tiny number of ${\mathrm{H}}^{+}$ ions are released when ${\mathrm{CH}}_3\mathrm{COOH}$ is diluted.
• It is regarded as a weak acid since it does not completely dissociate to release the ${\mathrm{H}}^{+}$ ions.

Explanation for the incorrect options:

(B)${\mathrm{H}}_2{\mathrm{SO}}_4$

• Sulfuric acid ${\mathrm{H}}_2{\mathrm{SO}}_4$completely ionizes to create ions.
• Acetic acid ${\mathrm{CH}}_3\mathrm{COOH}$ partly ionizes in an aqueous solution to generate ions.
• ${\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)\to {\mathrm{H}}^{+}\left(\mathrm{aq}\right)+{{\mathrm{SO}}_4}^{-}\left(\mathrm{aq}\right)$
• The more acidic character of sulfuric acid will be caused by a higher concentration of ${\mathrm{H}}^{+}$ ions.

(C)$\mathrm{HCl}$

• Because it dissociates almost entirely, $\mathrm{HCl}$ is a powerful acid.
• The chloride ion cannot receive the ${\mathrm{H}}^{+}$ ion and change back into $\mathrm{HCl}$.
• In conclusion, more free ${\mathrm{H}}^{+}$ ions are liberated into solution with stronger acids.

(D)${\mathrm{HNO}}_3$

• With a pH of 3.1, ${\mathrm{HNO}}_3$ is a quite strong acid.
• The ability of an acid to form hydronium ions by dissociation in water is what determines how strong the acid is.
• ${\mathrm{HNO}}_3$ acid is regarded as a strong acid since it totally dissociates into ${\mathrm{H}}^{+}$ and ${{\mathrm{NO}}_3}^{-}$-ions in an aqueous solution.

Therefore, the correct option is (A)${\mathrm{CH}}_3\mathrm{COOH}$