Question:

Among the following, the molecule expected to be stabilized by anion formation is :
\(\mathrm{C_2,\ O_2,\ NO,\ F_2}\)

Show Hint

A molecule is stabilised by gaining an electron if the extra electron goes into a bonding molecular orbital, raising the bond order.
Updated On: Nov 5, 2026
  • \(\mathrm{C_2}\)
  • \(\mathrm{NO}\)
  • \(\mathrm{O_2}\)
  • \(\mathrm{F_2}\)
Show Solution
collegedunia
Verified By Collegedunia

The Correct Option is A

Solution and Explanation

Bond orders by MO theory:
\(\mathrm{C_2}\) (12 e-): \(\sigma_{1s}^2\sigma_{1s}^{*2}\sigma_{2s}^2\sigma_{2s}^{*2}\pi_{2p}^4\); bond order = (8-4)/2 = 2. The next electron enters the bonding \(\sigma_{2p}\) orbital: \(\mathrm{C_2^-}\) has bond order 2.5, so it is stabilised.
\(\mathrm{O_2}\) (bond order 2): the extra electron goes into antibonding \(\pi^*_{2p}\): \(\mathrm{O_2^-}\) has bond order 1.5, destabilised.
NO (bond order 2.5): the extra electron goes into antibonding \(\pi^*_{2p}\): \(\mathrm{NO^-}\) has bond order 2, destabilised.
\(\mathrm{F_2}\) (bond order 1): extra electron goes into antibonding \(\sigma^*_{2p}\): \(\mathrm{F_2^-}\) has bond order 0.5, destabilised.
Hence only \(\mathrm{C_2}\) is stabilised by anion formation.
Answer: (1) \(\mathrm{C_2}\)
Was this answer helpful?
0
0

Top JEE Main Chemical bonding and molecular structure Questions

View More Questions