MHT CET Chemistry Question (2026) — Solution

Step-by-step solution

The given reaction is the acid-catalyzed dehydration of an alcohol. The reactant is 3,3-dimethyl-2-butanol. Step 1: Protonation of the hydroxyl group by H_2SO_4 to form a good leaving group (-OH_2^+). CH_3-C(CH_3)_2-CH(OH)-CH_3 + H^+ CH_3-C(CH_3)_2-CH(OH_2^+)-CH_3 Step 2: Loss of a water molecule to form a secondary (2^ ) carbocation. CH_3-C(CH_3)_2-CH(OH_2^+)-CH_3 CH_3-C(CH_3)_2-CH^+-CH_3 + H_2O Step 3: The 2^ carbocation undergoes a 1,2-methyl shift to form a more stable tertiary (3^ ) carbocation. CH_3-C(CH_3)_2-CH^+-CH_3 1,2-methyl shift CH_3-C^+(CH_3)-CH(CH_3)-CH_3 Step 4: Elimination of a proton (H^+) from the adjacent carbon atom yields the most substituted alkene as the major product, according to Saytzeff's rule. CH_3-C^+(CH_3)-CH(CH_3)-CH_3 CH_3-C(CH_3)=C(CH_3)-CH_3 + H^+ The major product formed is 2,3-dimethyl-2-butene. Answer: 2,3-dimethyl-2-butene