Solved: CHEMISTRY Question for NEET

NEET CHEMISTRYMedium

Which one of the following statements is correct?

BF $_3$ has non-zero dipole moment.

The dipole moment of NF $_3$ is greater than that of NH $_3$ .

Three canonical forms can be drawn for CO $_3^{2-}$ ion.

Three resonance structures can be drawn for ozone.

Analyze Option A ( $BF_3$ ): $BF_3$ has a symmetrical trigonal planar geometry. The resultant of two B-F bond moments is equal and opposite to the third B-F bond moment, resulting in a net dipole moment of zero .
Analyze Option B ( $NH_3$ vs $NF_3$ ): In $NH_3$ , the orbital dipole due to the lone pair is in the same direction as the resultant of the three N-H bond moments, reinforcing the effect. In $NF_3$ , the orbital dipole is in the direction opposite to the resultant of the three N-F bond moments. Consequently, the dipole moment of $NH_3$ (1.47 D) is greater than that of $NF_3$ (0.23 D) .
Analyze Option C ( $CO_3^{2-}$ ): The carbonate ion is resonance stabilized. Experimental findings show all C-O bonds are equivalent. This is described by three equivalent canonical forms where the double bond is delocalized over the three oxygen atoms .
Analyze Option D (Ozone): The ozone molecule ( $O_3$ ) is represented by two canonical forms (resonance structures) to explain the equality of its bond lengths .

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