Question

Acetic acid in liquid ammonia behaves as

• A. Weaker acid than that in water
• B. Stronger acid than that in water
• C. Base acid
• D. Neutral acid
• E. (C) and (D)

Hint:

This is known as the "leveling effect." A basic solvent increases the apparent strength of an acid, while an acidic solvent can make a strong acid appear weaker.

Answer 1

The Correct Option is B

Concept: The acidity of a substance depends on the solvent's ability to accept protons (basicity). Liquid ammonia is a more basic solvent than water, which influences the ionization of acids dissolved in it.

Step 1: {Compare the basicity of solvents.}
Ammonia (NH$_3$) is a stronger base than water (H$_2$O). This is because the lone pair on the nitrogen atom in ammonia is more available for protonation than the lone pairs on the oxygen atom in water.

Step 2: {Analyze the leveling effect.}
In a highly basic solvent like liquid ammonia, even relatively weak acids like acetic acid are forced to donate their protons completely. $$\text{CH}_3\text{COOH} + \text{NH}_3 \rightarrow \text{CH}_3\text{COO}^- + \text{NH}_4^+$$

Step 3: {Determine the relative acid strength.}
Because liquid ammonia accepts protons more readily than water, acetic acid ionizes to a much greater extent in ammonia. Therefore, it behaves as a stronger acid in liquid ammonia than it does in water.