A : Addition of `Br_(2)` in trans-but-2-ene in the presence of `C``CI_(4)` gives meso form.
R : The reaction occurs through anti addition.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1).
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2)
C. if Assertion is true statement but Reason is false, then mark (3)
D. If both Assertion and Reason are false statements, then mark (4)

Answer

To solve the question regarding the addition of \( Br_2 \) to trans-but-2-ene in the presence of \( CCl_4 \) and its resulting meso form, we can break it down into the following steps:

### Step 1: Understand the structure of trans-but-2-ene
Trans-but-2-ene is a symmetrical alkene with the following structure:
\[ \text{CH}_3-CH=CH-CH_3 \]
In this structure, the two methyl groups (CH₃) are on opposite sides of the double bond.

### Step 2: Identify the reaction conditions
The addition of \( Br_2 \) to alkenes typically occurs in a non-polar solvent like \( CCl_4 \). This solvent does not participate in the reaction, allowing for the bromine to add across the double bond.

### Step 3: Determine the mechanism of addition
The addition of \( Br_2 \) to alkenes occurs through an anti-addition mechanism. This means that the bromine atoms will add to opposite sides of the double bond.

### Step 4: Visualize the anti-addition
When \( Br_2 \) adds to trans-but-2-ene, the bromine atoms will add to the opposite sides of the double bond. This results in the formation of a dibromide where the two bromine atoms are positioned on opposite sides of the original double bond.

### Step 5: Analyze the stereochemistry
Due to the anti-addition mechanism, the product formed will be a meso compound. A meso compound has multiple stereocenters but is achiral due to an internal plane of symmetry. In this case, the product will have two bromine atoms added to the double bond, resulting in a structure that is symmetrical.

### Step 6: Conclude the assertion and reason
The assertion states that the addition of \( Br_2 \) to trans-but-2-ene in the presence of \( CCl_4 \) gives a meso form. The reason states that the reaction occurs through anti-addition. Both the assertion and reason are true, and the reason explains the assertion.

### Final Answer
Both the assertion (A) and reason (R) are true, and R explains A.

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