An organic compound `X(C_(4)H_(9)Br)` on treatment with alc, KOH gave isomeric product with the formula `C_(4)H_(8)`. On ozonolysis one of these gave only product `CH_(3)CHO` while the other gave two

Options

A. 2-bromobutane
B. 2-bromopentane
C. 1,2-dibromo butane
D. 3-bromopentene

Answer

To solve the problem, we need to identify the organic compound \( X \) with the formula \( C_4H_9Br \) that, upon treatment with alcoholic KOH, yields isomeric products with the formula \( C_4H_8 \). We also know that one of these products gives only acetaldehyde (\( CH_3CHO \)) upon ozonolysis, while the other gives two products.

### Step-by-Step Solution:

1. **Identify the Structure of Compound \( X \)**:
- The compound \( X \) has the formula \( C_4H_9Br \). This indicates it is a brominated alkane with four carbon atoms. The possible structures for \( C_4H_9Br \) include:
- 1-bromobutane
- 2-bromobutane
- 1-bromo-2-methylpropane
- 2-bromo-2-methylpropane

2. **Reaction with Alcoholic KOH**:
- When \( X \) reacts with alcoholic KOH, elimination occurs, leading to the formation of alkenes. The elimination can produce two isomeric alkenes from \( X \).
- The possible alkenes from \( 2-bromobutane \) are:
- 1-butene (\( CH_2=CH-CH_2-CH_3 \))
- 2-butene (\( CH_3-CH=CH-CH_3 \))

3. **Ozonolysis of the Alkenes**:
- Ozonolysis of alkenes involves the cleavage of the double bond and formation of carbonyl compounds.
- For 1-butene:
- Ozonolysis gives two moles of acetaldehyde (\( CH_3CHO \)).
- For 2-butene:
- Ozonolysis gives one mole of acetaldehyde (\( CH_3CHO \)) and one mole of propanal (\( CH_3CH_2CHO \)).

4. **Determine the Correct Alkyl Halide**:
- Since one alkene gives only acetaldehyde and the other gives two products, we can conclude that the compound \( X \) must be 2-bromobutane. This is because:
- 2-bromobutane leads to 1-butene (which gives two moles of acetaldehyde) and 2-butene (which gives acetaldehyde and propanal).

5. **Final Answer**:
- Therefore, the compound \( X \) is \( 2-bromobutane \).

### Summary of Findings:
- Compound \( X \) is \( 2-bromobutane \) (option A).