Which of the following is most acidic?

(A) Benzyl alcohol

(B) 2-Butanol

(C) tert-Butyl alcohol

(D) Hydroxybenzene

To determine which of the given compounds is the most acidic, we need to consider the structure of each compound and how it influences acidity. Acidity in organic compounds is often related to the stability of the conjugate base formed after deprotonation. Let's break down each option.

Understanding Acidity in Organic Compounds

Acidity is defined by the ability of a compound to donate a proton (H+). The more stable the conjugate base, the stronger the acid. Factors that influence acidity include electronegativity, resonance stabilization, and the inductive effect.

Analyzing Each Compound

• Benzyl alcohol (A): This compound has a hydroxyl group (-OH) attached to a benzyl group. When it loses a proton, the resulting phenoxide ion can be stabilized by resonance with the aromatic ring, making it relatively acidic.
• 2-Butanol (B)
• tert-Butyl alcohol (C): This alcohol has a tertiary carbon attached to the hydroxyl group. Similar to 2-butanol, the conjugate base lacks resonance stabilization and is further destabilized by steric hindrance from the bulky tert-butyl group, making it the least acidic of the three alcohols.
• Hydroxybenzene (D) (also known as phenol): This compound has a hydroxyl group directly attached to a benzene ring. The conjugate base, phenoxide ion, is highly stabilized by resonance, as the negative charge can be delocalized over the aromatic system, making phenol quite acidic.