In which of the following pairs of molecules/ions, both the species are not likely to exist?

In which of the following pairs of molecules/ions, both the species are not likely to exist?
  1. H 2 2 + ,  He 2
  2. H 2 - ,  He 2 2 +
  3. H 2 + ,  He 2 2 -
  4. H 2 - ,  He 2 2 -

Solution

(i)    H 2 2 + ⇒ B . O = 0 He 2 ⇒ B . O = 2 - 2 2 = 0 }

(ii)   H2-⇒B.O=2-12=0.5He22+⇒B.O=1

(iii)    H 2 + = B . O = 1 - 0 2 = 0 . 5 He 2 2 - = B . O = 4 - 2 2 = 1 . 0

(iv)    H 2 - ⇒ B . O = 2 - 1 2 = 0 . 5 He 2 2 - ⇒ B . O = 4 - 2 2 = 1 . 0


As both H22+ and He2 have zero bond order and hence do not exist.

Asked in: JEE Main 2013 (07 Apr)

Practice more Chemical Bonding and Molecular Structure questions on Aicharya