NEET 2020 · ChemistryMO theoryPrevious Year Question

Identify a molecule which does not exist.

Answer: (C) $He X_{2}$ . \textbf{Answer:} (C) $He X_{2}$ \textbf{Solution:} By MOT, $He X_{2}$ has equal electrons in bonding and antibonding MOs, giving bond order $= \frac{1}{2} (N_{b} - N_{a}) = \frac{1}{2} (2 - 2) = 0$ , so $He X_{2}$ does not exist.

A. $C X_{2}$
B. $O X_{2}$
C. $He X_{2}$ ✓
D. $Li X_{2}$

Correct Answer

Solution & Explanation

\textbf{Answer:} (C) $He X_{2}$ \textbf{Solution:} By MOT, $He X_{2}$ has equal electrons in bonding and antibonding MOs, giving bond order $= \frac{1}{2} (N_{b} - N_{a}) = \frac{1}{2} (2 - 2) = 0$ , so $He X_{2}$ does not exist. $C X_{2}$ , $O X_{2}$ and $Li X_{2}$ have positive bond orders and do exist.

🎯

43,000+ questions in हिंदी & English · one-tap toggle

Practice NEET 2020 Chemistry — free, with instant solutions

The app builds a daily goal from your weak topics and brings each question back just before you forget it — so what you solve today turns into marks on exam day.

Open →📚Practice all NEET Chemistry PYQs chapter-wise →💡Don't get it? Learn the Chemical Bonding concepts →

← Chemistry Q15 Chemistry Q17 →

More NEET PYQ solutions

ChemThe correct order of energies of the molecular orbitals of the N2 molecule is:ChemWhich amongst the following is an incorrect statement?ChemWhich of the following is paramagnetic?ChemWhich of the following diatomic molecular species has only bonds according to Molecular Orbital Theory?ChemConsider the following species: CN^+, CN^-, NO and CN. Which of these will have the highest bond order?ChemWhich one of the following pairs of species have the same bond order?ChemThe correct order of decreasing acidity of the following aliphatic acids is:ChemWhich one of the following reactions does NOT belong to Lassaigne's test?

More: All NEET 2020 Chemistry PYQs · NEET Chemistry PYQs · All NEET PYQs · Previous year papers