NEET · Chemistry · STD 11 - 4. Chemical bonding and molecular structure

Identify a molecule which does not exist.

A \(O _{2}\)
B \(He _{2}\)
C \(Li _{2}\)
D \(C _{2}\)

Verified Solution

Answer & Solution

Correct Answer

(B) \(He _{2}\)

Step-by-step Solution

Detailed explanation

\(He _{2}=\) Total electron \(=4\) \(=\sigma_{1 \sigma}^{2} \sigma_{1 \sigma}^{* 2} \Rightarrow B . O .=\frac{1}{2}[ Nb - Na ]=\frac{1}{2}[2-2]=0\)

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

Same subject

Match the Xenon compounds in Column\(-I\) with its structure in Column\(-II\) and assign the correct code

Column\(-I\)	Column\(-II\)
\((a)\) \(\mathrm{XeF}_{4}\)	\((i)\) pyramidal
\((b)\) \(\mathrm{XeF}_{6} \)	\((ii)\) square planar
\((c)\) \(\mathrm{XeOF}_{4}\)	\((iii)\) distorted octahedral
\((d)\) \(\mathrm{XeO}_{3} \)	\((iv)\) square pyramidal

code : \((a) \quad (b)\quad (c) \quad (d)\)

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