Question

In which of the following molecules, 2\(\pi\) bonds are present?

• A. C\(_2\)H\(_6\)
• B. C\(_2\)H\(_4\)
• C. C\(_2\)H\(_2\)
• D. C\(_3\)H\(_6\)

Hint:

In a triple bond, there are two \(\pi\) bonds and one sigma bond, as seen in acetylene (C\(_2\)H\(_2\)).

Answer 1

The Correct Option is C

Step 1: Understanding \(\pi\) bonds.
A \(\pi\) bond is formed by the sideways overlap of p-orbitals. Alkenes and alkynes contain \(\pi\) bonds. In C\(_2\)H\(_2\) (ethyne or acetylene), the carbon-carbon triple bond consists of one sigma bond and two \(\pi\) bonds.

Step 2: Analyzing the options.
(A) C\(_2\)H\(_6\): This is ethane, which contains only sigma bonds.
(B) C\(_2\)H\(_4\): This is ethene, which contains one \(\pi\) bond along with the sigma bond in the carbon-carbon double bond.
(C) C\(_2\)H\(_2\): Correct — This molecule contains two \(\pi\) bonds in the triple bond.
(D) C\(_3\)H\(_6\): This is cyclohexene, which contains one \(\pi\) bond in the carbon-carbon double bond.

Step 3: Conclusion.
The correct answer is (C) C\(_2\)H\(_2\), as it contains two \(\pi\) bonds.