Question

\( (\text{CH}_3)_3\text{CH} \xrightarrow{\text{KMnO}_4} \text{X} \xrightarrow[\text{573K}]{\text{Cu}} \text{Y} \). The number of \( sp^3 \) and \( sp^2 \) carbons in Y are respectively

• A. 3, 1
• B. 1, 3
• C. 2, 2
• D. 4, 0

Hint:

Cu/573K Reactions: - Primary Alcohol \(\to\) Aldehyde (Dehydrogenation) - Secondary Alcohol \(\to\) Ketone (Dehydrogenation) - Tertiary Alcohol \(\to\) Alkene (Dehydration)

Answer 1

The Correct Option is A

Step 1: Reaction Analysis:

1. Oxidation with KMnO₄:
Alkanes with a tertiary hydrogen atom (like isobutane) can be oxidized by strong oxidizing agents like KMnO₄ to corresponding tertiary alcohols.
(CH₃)₃CH → (CH₃)₃C–OH (tert-Butyl alcohol, X)

2. Dehydrogenation/Dehydration with Cu at 573 K:
Tertiary alcohols passed over heated Copper (Cu) at 573 K undergo dehydration (elimination of water) to form alkenes.
(CH₃)₃C–OH → CH₃–C(CH₃)=CH₂ + H₂O
Product Y is Isobutylene (2-methylpropene).

Step 2: Counting Hybridized Carbons in Y:

Structure of Y: CH₃–C(CH₃)=CH₂

Carbons:
1. Terminal =CH₂ → double bonded → sp²
2. Central carbon (=C<) → double bonded → sp²
3. Two CH₃ groups → single bonded → sp³

Total sp² carbons = 2
Total sp³ carbons = 2

Step 3: Conclusion:

Thus, the number of sp³ and sp² carbons are (2, 2).

Step 4: Final Answer:
The number of sp³ carbons is 2, and sp² carbons is 2. (Option 3)