See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

## Solution **Reaction: Phenyl magnesium bromide ($PhMgBr$) + t-Butyl alcohol** **Step 1: Identify the Grignard reagent's reactivity** $PhMgBr$ is a strong nucleophile and strong base. It reacts with protic compounds (those with active $-OH$ or $-NH$ groups). **Step 2: Compare reactivity of alcohol types** t-Butyl alcohol is a **tertiary alcohol** with a sterically hindered $-OH$ group. When a Grignard reagent encounters such a bulky alcohol, it acts as a **base rather than a nucleophile** because: - Steric hindrance prevents nucleophilic attack on carbon - The acidic hydrogen is more accessible **Step 3: Acid-base reaction occurs** $$PhMgBr + (CH_3)_3C-OH \rightarrow PhH + (CH_3)_3C-OMgBr$$ The Grignard reagent abstracts the acidic proton from the alcohol, forming **benzene ($Ph-H$)** and magnesium alkoxide. **Step 4: Why other options are wrong** - (A) $Ph-OH$: Would require insertion of oxygen (doesn't happen) - (C) & (D): Would require nucleophilic addition to carbon (blocked by steric hindrance) **Answer: (B) $Ph-H$ (Benzene)** The basic nature of Grignard reagents dominates over steric hindrance in this case, leading to proton abstraction.