Which of the following reagents can be used as the basis for a simple chemical test for distinguishing 1-butene from `CH_(3)CH_(2)CH_(2)CH_(2)OH` ?

Options

A. `Br_(2)// C Cl_(4)`
B. Dilute aqueous `KMnO_(4)`
C. `CrO_(3)`/aqueous `H_(2)SO_(4)`
D. none of these

Answer

To distinguish between 1-butene (an alkene) and 1-butanol (an alcohol), we can use a reagent that specifically reacts with the carbon-carbon double bond present in alkenes. Here’s a step-by-step solution to the question:

### Step 1: Identify the Compounds
1-butene (C4H8) is an alkene with a double bond between the first and second carbon atoms. Its structure is:
- CH2=CH-CH2-CH3

1-butanol (C4H10O) is an alcohol with a hydroxyl (-OH) group attached to the first carbon. Its structure is:
- CH3-CH2-CH2-CH2OH

### Step 2: Understand the Nature of the Compounds
- Alkenes (like 1-butene) contain a carbon-carbon double bond, which is a site of unsaturation.
- Alcohols (like 1-butanol) do not have a double bond and are saturated.

### Step 3: Choose a Suitable Reagent
To distinguish between these two compounds, we need a reagent that reacts with the double bond in alkenes but not with alcohols.

### Step 4: Analyze the Options
1. **Br2 in CCl4**: This reagent is known to react with alkenes. The bromine (Br2) adds across the double bond, leading to decolorization of the brown color of bromine, indicating the presence of an alkene.
2. **Dilute aqueous KMnO4**: This reagent can also oxidize alkenes, leading to a color change, but it is less specific than bromine.
3. **CrO3 in aqueous H2SO4**: This is a strong oxidizing agent that can oxidize alcohols but is not specific for distinguishing between an alkene and an alcohol.
4. **None of these**: This option suggests that none of the reagents are suitable, which is incorrect.

### Step 5: Conclusion
The best reagent for distinguishing 1-butene from 1-butanol is **Br2 in CCl4**. The reaction of bromine with 1-butene will lead to decolorization, while 1-butanol will not react in the same manner.

### Final Answer
**Br2 in CCl4**

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