cis-2-Butene on reaction with Baeyer's reagent gives:

Options

A. meso-geminal diol
B. racemic-vicinal diol
C. meso-vicinal diol
D. none of these

Answer

To determine the product of the reaction between cis-2-butene and Baeyer's reagent, we can follow these steps:

### Step 1: Identify the Structure of cis-2-butene
Cis-2-butene is an alkene with the following structure:
- It has four carbon atoms (C4) and a double bond between the second and third carbon atoms.
- The structure can be represented as:

CH3-CH=CH-CH3

In the cis isomer, the two methyl (CH3) groups are on the same side of the double bond.

### Step 2: Understand Baeyer's Reagent
Baeyer's reagent is an alkaline solution of potassium permanganate (KMnO4). It is used to test for the presence of unsaturation (double or triple bonds) in organic compounds. When alkenes react with Baeyer's reagent, they undergo oxidation.

### Step 3: Reaction Mechanism
When cis-2-butene reacts with Baeyer's reagent:
- The double bond in cis-2-butene is oxidized.
- The reaction leads to the formation of a diol (a compound with two hydroxyl groups).

### Step 4: Determine the Product
The product of the reaction between cis-2-butene and Baeyer's reagent is:
- The double bond is converted into a single bond, and two hydroxyl (OH) groups are added across the former double bond.
- The resulting compound is 2,3-butanediol, specifically a vicinal diol because the hydroxyl groups are on adjacent carbon atoms.

### Step 5: Identify the Stereochemistry
- Since the original compound was cis, the product will have a plane of symmetry, making it a meso compound.
- Therefore, the product can be identified as meso-2,3-butanediol.

### Final Answer
The reaction of cis-2-butene with Baeyer's reagent produces **meso-2,3-butanediol**.

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