JEE Chemistry 2026 Question with Solution

Given: Statements are given about dipole moment, bond order, formal charge, and octet rule for different molecules/ions.

Find: Which statements are correct and hence the correct option.

1. Statement A: $\mathrm{NH_3}$ has a higher dipole moment than $\mathrm{NF_3}$ due to stronger $\mathrm{N-H}$ bond polarity and vector addition. Therefore, statement A is false.

2. Statement B: $\mathrm{BeH_2}$ is linear and symmetrical, so its dipole moments cancel out. Therefore, its dipole moment is $0$ and statement B is true.

3. Statement C: Bond order of $\mathrm{O_2^{2-}}$ is $1$ and bond order of $\mathrm{F_2}$ is also $1$. Therefore, statement C is true.

4. Statement D: In ozone $\mathrm{(O_3)}$, the central oxygen atom has a formal charge of $-1$. Therefore, statement D is true.

5. Statement E: $\mathrm{NO_2}$ is an odd-electron molecule and does not satisfy the octet rule. Therefore, statement E is false.

Thus, the correct statements are B, C and D only, which corresponds to option C.

Conclusion: The correct option is C.

Given: Five statements about $\mathrm{NF_3}$, $\mathrm{NH_3}$, $\mathrm{BeH_2}$, $\mathrm{O_2^{2-}}$, $\mathrm{F_2}$, ozone, and $\mathrm{NO_2}$.

Find: Evaluate each statement using molecular geometry and electron count.

The key checks are:

• dipole moment depends on both bond polarity and molecular geometry,
• bond order depends on electron distribution,
• formal charge is obtained from Lewis structure,
• octet rule must be checked from total valence electrons.

Applying these checks:

• For $\mathrm{NF_3}$ and $\mathrm{NH_3}$, $\mathrm{NH_3}$ has the higher dipole moment, so statement A is false.
• $\mathrm{BeH_2}$ is linear, therefore net dipole moment is zero, so statement B is true.
• $\mathrm{O_2^{2-}}$ and $\mathrm{F_2}$ both have bond order $1$, so statement C is true.
• In ozone, the central oxygen carries formal charge $-1$, so statement D is true.
• $\mathrm{NO_2}$ is an odd-electron species and does not satisfy the octet rule for all atoms, so statement E is false.

Therefore, only B, C and D are correct.

Conclusion: The correct option is C. Note that this also matches option (3) in the source listing.