Which is the most suitable reagent for the following transformation?
`CH_(3) - CH = CH - CH_(2) - overset(OH) overset(|)(CH) - CH_(3) rarr` ltrbgt `CH_(3) - CH = CH - CH_(2)CO_(2)H`

Options

A. alkaline `KMnO_4`
B. `I_2//NaOH`
C. Tollen's reagent
D. `CrO_3//CS_2`

Answer

To solve the transformation of the compound from `CH3-CH=CH-CH2-CHOH-CH3` to `CH3-CH=CH-CH2-COOH`, we need to identify the most suitable reagent for this reaction.

### Step 1: Analyze the starting compound
The starting compound is `CH3-CH=CH-CH2-CHOH-CH3`, which has a double bond and an alcohol (-OH) group.

### Step 2: Identify the desired product
The desired product is `CH3-CH=CH-CH2-COOH`, which contains a carboxylic acid (-COOH) group instead of the alcohol group.

### Step 3: Determine the type of reaction
The transformation involves the conversion of an alcohol to a carboxylic acid. This suggests an oxidation reaction where the alcohol group is oxidized to a carboxylic acid.

### Step 4: Choose the appropriate reagent
To achieve this transformation, we can use iodine (I2) in the presence of sodium hydroxide (NaOH). This combination is known to facilitate the oxidation of alcohols to carboxylic acids.

### Step 5: Write the reaction
The reaction can be summarized as follows:
1. The alcohol group (-OH) is oxidized to a carboxylic acid (-COOH) using I2 and NaOH.
2. The double bond remains intact during this transformation.

### Conclusion
Thus, the most suitable reagent for this transformation is **I2 + NaOH**.

### Final Answer
The answer is option **B: I2 + NaOH**.

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