In each of the following questions, a Statement-I is given followed by corresponding Statement-II just below. Mark the correct answer as indicated.

Statement-I: The H atom of acetylene is more acidic than ethylene.

Statement-II: \(sp\)-hybridized carbon is more electronegative than \(sp^2\)-hybridised carbon.

If both Statement-I and Statement- II are true and reason is the correct explanation of assertion.

The correct answer is option 1. If both Statement-I and Statement- II are true and reason is the correct explanation of assertion.

Let us break down and explain each statement and their relationship in details:

Statement-I: The H atom of acetylene is more acidic than ethylene.

Acidity of a hydrogen atom attached to a carbon atom in an alkene or alkyne depends on the stability of the conjugate base formed after deprotonation. Acetylene (\(C_2H_2\)) has a triple bond between two carbon atoms, resulting in the hydrogen attached to an \(sp\)-hybridized carbon atom. The \(sp\)-hybridized carbon is more electronegative and stabilizes negative charge better compared to an \(sp^2\)-hybridized carbon. Ethylene (\(C_2H_4\)), on the other hand, has a double bond between two carbon atoms, where the hydrogen is attached to an \(sp^2\)-hybridized carbon.

Acidity Reasoning: The higher electronegativity of the \(sp\)-hybridized carbon in acetylene makes the hydrogen more acidic because the resulting acetylide ion (conjugate base) is more stabilized by the electronegative \(sp\)-hybridized carbon. This stabilization lowers the energy of the conjugate base, making the acid (acetylene) stronger.

Statement-II: \(sp\)-hybridized carbon is more electronegative than \(sp^2\)-hybridized carbon.

\(sp\)-hybridized carbon has a higher s-character (50%) compared to \(sp^2\)-hybridized carbon (33.3%). Electronegativity generally increases with increasing s-character because the s-orbital is closer to the nucleus and experiences stronger nuclear attraction. Therefore, \(sp\)-hybridized carbon, having more s-character, is more electronegative than \(sp^2\)-hybridized carbon.

Correct Answer Analysis:

Option 1: If both Statement-I and Statement-II are true and reason is the correct explanation of assertion.

This option correctly aligns with the explanations provided:

Statement-I is true because the acidity of acetylene's hydrogen is enhanced by the higher electronegativity and stability provided by the \(sp\)-hybridized carbon.

Statement-II is true because \(sp\)-hybridized carbon is indeed more electronegative than \(sp^2\)-hybridized carbon due to its higher s-character. Furthermore, Statement-II provides a valid explanation (reason) for Statement-I, elucidating why the hydrogen atom in acetylene is more acidic compared to ethylene.

Conclusion: The correct answer, option 1, accurately reflects the factual correctness of both statements and their explanatory relationship regarding the acidity of acetylene and the electronegativity difference between \(sp\)- and \(sp^2\)-hybridized carbons. This understanding is crucial in organic chemistry to explain the relative acidity of alkynes versus alkenes and the influence of hybridization on electronegativity.