Question

Which of the following statements regarding Pi \((π)\) bond is NOT true ?

• A. It is weaker than sigma bond.
• B. It is formed by lateral overlapping of two half filled P orbitals.
• C. It is formed after the formation of sigma bond.
• D. The presence of Pi \((π)\) bond increases the bond length of covalent bond.

Hint:

A pi bond adds to bonding between two atoms, so it pulls them closer.

Answer 1

The Correct Option is D

Step 1: Compare with known bond lengths:
Carbon-carbon bond lengths are 154 pm (single), 134 pm (double) and 120 pm (triple). Each extra pi bond shortens the bond.

Step 2: Judge each statement:
A pi bond has sideways overlap of p orbitals, which is weaker than head-on sigma overlap. It forms only after the sigma bond is in place. Both these facts agree with (A), (B) and (C).
Statement (D) says the pi bond increases the bond length, which is the opposite of what we see in the data above. So (D) is the false one.

Final Answer:
The pi bond shortens the bond, so (D) is not true. \[ \boxed{\text{(D)}} \]