Assertion : `C_(2)H_(2)` molecule is linear.
Reason : In `C_(2)H_(2)` carbon atoms remain unhybridized.

Options

A. Assertion and reason both are correct statements and reason is correct explanation for assertion.
B. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
C. Assertion is correct statement but reason is wrong statement.
D. Assertion is wrong statement but reason is correct statement.

Answer

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

**Step 1: Analyze the Assertion**
The assertion states that the `C2H2` molecule is linear. To determine if `C2H2` (ethyne or acetylene) is linear, we need to consider its molecular geometry.

- In `C2H2`, there are two carbon atoms and two hydrogen atoms. Each carbon atom forms a triple bond with the other carbon atom and a single bond with a hydrogen atom.
- The geometry around each carbon atom, which is `sp` hybridized, leads to a linear arrangement of the atoms. The bond angle between the hydrogen-carbon-hydrogen is 180 degrees.

**Conclusion for Step 1**: The assertion is correct; `C2H2` is indeed linear.

**Step 2: Analyze the Reason**
The reason states that in `C2H2`, carbon atoms remain unhybridized.

- To understand this, we need to look at the hybridization of the carbon atoms in `C2H2`. The ground state electronic configuration of carbon is `1s2 2s2 2p2`. In the excited state, one of the 2s electrons is promoted to the 2p orbital, resulting in the configuration `1s2 2s1 2p2`.
- In `C2H2`, each carbon atom undergoes hybridization to form two `sp` hybrid orbitals (one for the sigma bond with hydrogen and one for the sigma bond with the other carbon). The remaining two unhybridized p orbitals (2p) form two pi bonds with the other carbon atom.
- Therefore, the carbon atoms in `C2H2` are not unhybridized; they are indeed hybridized.

**Conclusion for Step 2**: The reason is incorrect; the carbon atoms are hybridized, not unhybridized.

**Final Conclusion**: The assertion is true, but the reason is false. Therefore, the correct answer is that the assertion is correct, but the reason is incorrect.