See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Solution **Step 1: Identify compound A** $Ph-C \equiv CH$ (phenylacetylene) undergoes hydration with $aq. H_2SO_4$ and $Hg^{2+}$ catalyst. This follows **Markovnikov's rule**: the $OH$ adds to the more substituted carbon of the triple bond. $$Ph-C \equiv CH + H_2O \rightarrow Ph-C(=O)-CH_3$$ **Compound A = Acetophenone** ($PhCOCH_3$) **Step 2: Identify compound B** Acetophenone (A) reacts with $CH_3MgI$ (Grignard reagent): $$PhCOCH_3 + CH_3MgI \rightarrow Ph-C(OMgI)(CH_3)_2$$ After aqueous workup ($H_2O$), the $OMgI$ is replaced by $OH$: $$Ph-C(OH)(CH_3)_2$$ This is a **tertiary alcohol** with phenyl and two methyl groups attached to the same carbon. **Step 3: Match with options** - **(A)** $PhCOCH_3$ — ketone (wrong) - **(B)** $PhCH_2CHOHCH_3$ — secondary alcohol (wrong) - **(C)** $\ce{Ph-C(OH)(CH3)2}$ — tertiary alcohol ✓ - **(D)** $PhCH_2COCH_3$ — ketone (wrong) **Answer: (C)** is correct because Grignard addition to a ketone produces a tertiary alcohol after hydrolysis.