An organic compound (X) with molecular formula $\mathrm{C}_{3} \mathrm{H}_{6} \mathrm{O}$ is not readily oxidised. On reduction it gives $\left(\mathrm{C}_{3} \mathrm{H}_{8} \mathrm{O}(\mathrm{Y})\right.$ which reacts with HBr to give a bromide (Z) which is converted to Grignard reagent. This Grignard reagent on reaction with (X) followed by hydrolysis give 2,3-dimethylbutan-2-ol. Compounds (X), (Y) and (Z) respectively are:
An organic compound (X) with molecular formula $\mathrm{C}_{3} \mathrm{H}_{6} \mathrm{O}$ is not readily oxidised. On reduction it gives $\left(\mathrm{C}_{3} \mathrm{H}_{8} \mathrm{O}(\mathrm{Y})\right.$ which reacts with HBr to give a bromide (Z) which is converted to Grignard reagent. This Grignard reagent on reaction with (X) followed by hydrolysis give 2,3-dimethylbutan-2-ol. Compounds (X), (Y) and (Z) respectively are:
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- $\mathrm{CH}_{3} \mathrm{COCH}_{3}, \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{OH}, \mathrm{CH}_{3} \mathrm{CH}(\mathrm{Br}) \mathrm{CH}_{3}$
- $\mathrm{CH}_{3} \mathrm{COCH}_{3}, \mathrm{CH}_{3} \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_{3}, \mathrm{CH}_{3} \mathrm{CH}(\mathrm{Br}) \mathrm{CH}_{3}$
- $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CHO}, \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{OH}, \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Br}$
- $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CHO}, \mathrm{CH}_{3} \mathrm{CH}=\mathrm{CH}_{2}, \mathrm{CH}_{3} \mathrm{CH}(\mathrm{Br}) \mathrm{CH}_{3}$
The Correct Option is B
Approach Solution - 1
The problem involves identifying the correct organic compounds (X), (Y), and (Z) based on their chemical behaviors and structural transformations. Let's solve this step-by-step:
- Compound (X) has the molecular formula \(\mathrm{C}_{3} \mathrm{H}_{6} \mathrm{O}\) and is not readily oxidized. A common compound with this molecular formula is acetone (propanone), which is a ketone. Ketones generally resist oxidation under mild conditions.
- Upon reduction, compound (X) gives compound (Y) with the formula \(\mathrm{C}_{3} \mathrm{H}_{8} \mathrm{O}\). A viable reduction product of acetone is isopropanol (2-propanol) because ketones reduce to secondary alcohols.
- Compound (Y), i.e., isopropanol, reacts with HBr to form compound (Z). This reaction is characteristic of alcohols converting to alkyl halides, thus forming isopropyl bromide (2-bromopropane).
- This compound (Z), isopropyl bromide, is converted into a Grignard reagent. When reacted with a ketone like acetone (compound X), followed by hydrolysis, Grignard reagents typically add to the carbonyl group. Thus, the formation of the tertiary alcohol, 2,3-dimethylbutan-2-ol, confirms the interactions.
Based on the above reasoning, the correct identities are:
- Compound (X): Acetone (\(\mathrm{CH}_{3} \mathrm{COCH}_{3}\))
- Compound (Y): Isopropanol (2-propanol, \(\mathrm{CH}_{3} \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_{3}\))
- Compound (Z): Isopropyl bromide (2-bromopropane, \(\mathrm{CH}_{3} \mathrm{CH}(\mathrm{Br}) \mathrm{CH}_{3}\))
Thus, the correct option is
$\mathrm{CH}_{3} \mathrm{COCH}_{3}, \mathrm{CH}_{3} \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_{3}, \mathrm{CH}_{3} \mathrm{CH}(\mathrm{Br}) \mathrm{CH}_{3}$
Approach Solution -2
1. Compound (X): - $\mathrm{CH}_{3} \mathrm{COCH}_{3}$ (Acetone)
2. Reduction to (Y): - $\mathrm{CH}_{3} \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_{3}$ (Isopropyl alcohol)
3. Reaction with HBr to form (Z): - $\mathrm{CH}_{3} \mathrm{CH}(\mathrm{Br}) \mathrm{CH}_{3}$ (2-Bromopropane)
4. Grignard reagent and reaction with (X): - The Grignard reagent formed from (Z) reacts with acetone to form 2,3-dimethylbutan-2-ol after hydrolysis.
Therefore, the correct answer is (2) $\mathrm{CH}_{3} \mathrm{COCH}_{3}, \mathrm{CH}_{3} \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_{3}, \mathrm{CH}_{3} \mathrm{CH}(\mathrm{Br}) \mathrm{CH}_{3}$.
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