Question

Identify the correct answer

• A. Three resonance structure can be drawn for ozone
• B. BF₃ has non-zero dipole moment
• C. Dipole moment of NF₃ is greater than that of NH₃
• D. Three canonical forms can be drawn for \(CO^{2-}_3 \)ion

Answer 1

The Correct Option is D

Step 1: Analyze Option (1) - BF₃

BF₃ is a planar molecule with B-F bonds arranged symmetrically. The dipole moments of the B-F bonds cancel each other, resulting in a zero dipole moment for the molecule. Thus, option (1) is false.

Step 2: Analyze Option (2) - Dipole Moment of NF₃ vs NH₃

In NF₃, fluorine is more electronegative than nitrogen, and the dipoles do not cancel, so NF₃ has a non-zero dipole moment.

NH₃ also has a non-zero dipole moment, but NF₃ has a greater dipole moment due to the greater electronegativity of fluorine. Thus, option (2) is true.

Step 3: Analyze Options (3) and (4)

Option (3): The Carbonate Ion (CO₃²⁻)

The carbonate ion (CO₃²⁻) has three resonance structures with equal contribution, so option (3) is true.

Option (4): The Ozone Molecule (O₃)

The ozone molecule (O₃) has two major resonance structures, so option (4) is true.

Step 4: Conclusion

The correct answer is:

Option (4): Three canonical forms can be drawn for the CO₃²⁻ ion.