Ques. 1JEE Advanced 2024 (Paper-1)
The option(s) in which at least three molecules follow Octet Rule is(are)
- CO2, C2H4, NO and HCl
- NO2, O3, HCl and H2SO4
- BCl3, NO, NO2 and H2SO4
- CO2, BCl3, O3 and C2H4
Answer
(1) CO2, C2H4, NO and HCl, (4) CO2, BCl3, O3 and C2H4
Solution
Exceptions to octet rule: odd-electron molecules (NO, NO2), incomplete octet (BCl3, 6 electrons on B) and expanded octet (H2SO4, 12 electrons on S as per NCERT).
Follow octet: CO2, C2H4, O3, HCl (Cl has an octet; H its duplet).
(A) CO2, C2H4, HCl → 3 follow – correct.
(B) only O3, HCl → 2. (C) none → 0.
(D) CO2, O3, C2H4 → 3 follow – correct.
Answer: (A), (D)