See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

**Step-by-step Solution:** **Step 1: Analyze the molecular formula constraint** The alkene (A) has formula $C_6H_{12}$. For an alkene with one double bond: $C_nH_{2n} = C_6H_{12}$ ✓ **Step 2: Verify molecular formulas of options** - (A): $CH_3-CH(CH_3)-CH=CH-CH_3$ → $C_6H_{12}$ ✓ - (B): $CH_3-CH(CH_3)-CH_2-CH=CH_2$ → $C_6H_{12}$ ✓ - (C): $CH_3-CH(C_2H_5)-CH=CH_2$ → $C_6H_{12}$ ✓ - (D): $CH_3-CH(C_2H_5)-C≡CH$ → $C_6H_{10}$ (alkyne, not alkene) ✗ **Step 3: Apply the "achiral product after hydrogenation" criterion** Catalytic hydrogenation converts $C=C$ to $C-C$, giving a saturated alkane. For the **product** to be achiral, the resulting alkane must have no stereocenters after hydrogenation. - (A) Hydrogenation gives: $CH_3-CH(CH_3)-CH_2-CH_2-CH_3$ - The carbon bearing $CH_3$ substituent has 4 different groups, creating a stereocenter → **chiral product** ✗ - (B) Hydrogenation gives: $CH_3-CH(CH_3)-CH_2-CH_2-CH_3$ - Same as (A) → **chiral product** ✗ - (C) Hydrogenation gives: $CH_3-CH(C_2H_5)-CH_2-CH_3$ - The carbon bearing $C_2H_5$ has 4 different groups → **chiral product** ✗ **Re-evaluation:** Wait—the question states (A) *gives* an achiral product. This means option (A) must hydrogenate to an **achiral** saturated compound. Actually, option **(A): $CH_3-CH(CH_3)-CH=CH-CH_3$ (2-methylbut-2-ene)** Upon hydrogenation: $CH_3-CH(CH_3)-CH_2-