Question

Identify the molecules which have sp-hybridized carbon(s) from the list given under:
I. Ethane nitrile
II. Buta-1,3-diene
III. Propa-1,2-diene
IV. Ethyne
V. Benzene

• A. I, II, III only
• B. II, III, IV only
• C. III, IV, V only
• D. I, III, IV only

Hint:

sp-hybridized carbons are involved in linear geometry with 180° bond angles, typically in triple bonds or cumulated double bonds.

Answer 1

The Correct Option is D

Step 1: Recall sp-hybridisation signature.
sp carbon appears in: (1) triple bonds (linear geometry) and (2) cumulated double bonds (allene-type, two consecutive C=C).

Step 2: Screen each molecule.
I (CH\(_3\)CN): the nitrile carbon carries a triple bond -- sp. III (CH\(_2\)=C=CH\(_2\)): middle carbon has two consecutive double bonds -- sp. IV (HC\(\equiv\)CH): both carbons sp. II (buta-1,3-diene) and V (benzene) are all sp\(^2\).
\[ \boxed{I,\ III,\ IV} \]