Arrange the following alcohols in decreasing order of acidity:

Choose the correct answer from the options given below:

(D), (A), (C), (B)

The correct answer is Option (4) → (D), (A), (C), (B)

Reasoning:
Acidity of alcohols depends on the stability of the alkoxide ion formed after loss of H⁺. Alkyl groups show a +I (electron-donating) effect, which destabilizes the negative charge on oxygen and reduces acidity.

• D (methanol) has no electron-donating alkyl groups → most acidic.

• A (ethanol) has one alkyl group → acidity decreases slightly.

• C (isopropanol) has two alkyl groups → acidity decreases further.

• B (tert-butanol) has three alkyl groups → strongest +I effect → least acidic.

Hence, acidity decreases in the order: methanol > ethanol > isopropanol > tert-butanol.

Decreasing order of acidity:

$\text{D (CH₃OH)} > \text{A (CH₃CH₂OH)} > \text{C ((CH₃)₂CH–OH)} > \text{B ((CH₃)₃C–OH)}$