Assertion. Acetylene reacts with sodamide te evolve `H_2` gas
Reason. Acetylene is a weaker acid than ammonia

Options

A. If both assertion and reason are true, and reason is the true explanation of the assertion.
B. If both assertion and reason are true, but reason is not the true explanation of the assertion.
C. If assertion is true, but reason is false.
D. If both assertion and reason are false

Explanation

To solve the question, we need to analyze both the assertion and the reason provided.

### Step 1: Understanding the Assertion
The assertion states that acetylene reacts with sodamide to evolve hydrogen gas (H₂).

- **Acetylene (C₂H₂)** has a structure of H-C≡C-H, where the carbon atoms are sp-hybridized.
- **Sodamide (NaNH₂)** is a strong base and can deprotonate acetylene.

When acetylene reacts with sodamide, the hydrogen atom attached to the carbon is acidic enough to be removed by the strong base, resulting in the formation of sodium acetylide (NaC≡C) and ammonia (NH₃). The reaction can be represented as:
\[ \text{C}_2\text{H}_2 + \text{NaNH}_2 \rightarrow \text{NaC}_2\text{H} + \text{NH}_3 \]

This reaction indeed evolves hydrogen gas, confirming the assertion is correct.

### Step 2: Understanding the Reason
The reason states that acetylene is a weaker acid than ammonia.

- **Acidity** is determined by the stability of the conjugate base formed after deprotonation.
- When acetylene loses a hydrogen ion (H⁺), it forms the acetylide ion (C≡C⁻). When ammonia loses a hydrogen ion, it forms the amide ion (NH₂⁻).

To compare their acidity:
1. The conjugate base of acetylene (C≡C⁻) is relatively stable due to the sp-hybridization of the carbon atom, which holds the negative charge more effectively.
2. The conjugate base of ammonia (NH₂⁻) is less stable because the negative charge is held by a less electronegative atom (nitrogen) compared to carbon.

Thus, acetylene is actually a stronger acid than ammonia, making the reason incorrect.

### Conclusion
- The assertion is correct: Acetylene reacts with sodamide to evolve hydrogen gas.
- The reason is incorrect: Acetylene is not a weaker acid than ammonia; it is actually a stronger acid.

### Final Answer
The assertion is correct, but the reason is incorrect.

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