Statement-1:Reduction of But-2-yne of Na/liq. `NH_3` gives
trans-But-2-ene.
Statement-2: It is an example of 'anti' addition.

Options

A. Statement-1 is True, Statement-2 is True, Statement-2 is a correct explanation for Statement-1
B. Statement-1 is True, Statement-2 is True, Statement-2 is NOT
a correct explanation for Statement-1
C. Statement-1 is True, Statement-2 is False.
D. Statement-1 is False, Statement-2 is True.

Answer

To solve the question, we need to analyze both statements regarding the reduction of But-2-yne using sodium (Na) in liquid ammonia (NH₃) and determine their validity.

### Step-by-Step Solution:

1. **Identify the Compound**:
- But-2-yne is represented as CH₃C≡CCH₃. It is an alkyne with a triple bond between the second and third carbon atoms.

2. **Understand the Reaction Conditions**:
- The reaction involves sodium metal in liquid ammonia, which is known to facilitate the Birch reduction. This process is used to reduce alkynes to alkenes.

3. **Reaction Mechanism**:
- In the Birch reduction, the triple bond of the alkyne undergoes reduction. The sodium donates electrons, and in the presence of liquid ammonia, protons (H⁺) are added to the alkene formed.

4. **Formation of Product**:
- The reduction of But-2-yne leads to the formation of trans-But-2-ene (CH₃CH=CHCH₃). The structure of trans-But-2-ene has the two methyl (CH₃) groups on opposite sides of the double bond.

5. **Determine Stereochemistry**:
- The formation of trans-But-2-ene indicates that the reaction proceeds via an anti-addition mechanism. This means that the addition of hydrogen atoms occurs on opposite sides of the double bond, resulting in the trans configuration.

6. **Evaluate the Statements**:
- **Statement 1**: "Reduction of But-2-yne by Na/liquid NH₃ gives trans-But-2-ene."
- This statement is **True**.
- **Statement 2**: "It is an example of 'anti' addition."
- This statement is also **True** as the formation of trans-But-2-ene is a result of anti-addition.

7. **Conclusion**:
- Both statements are true, and Statement 2 correctly explains Statement 1. Therefore, the answer is that both statements are true, and Statement 2 is the correct explanation for Statement 1.

### Final Answer:
- Statement 1 is true. Statement 2 is true and is a correct explanation for Statement 1.