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Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : NH3 and NF3 molecule have pyramidal shape with a lone pair of electrons on nitrogen atom. The resultant dipole moment of NH3 is greater than that of NF3. Reason (R) : In NH3, the orbital dipole due to lone pair is in the same direction as the resultant dipole moment of the N-H bonds. F is the most electronegative element. In the light of the above statements, choose the correct answer from the options given below: (1) Both (A) and (R) are true and (R) is the correct explanation of (A) (2) (A) is false but (R) is true (3) (A) is true but (R) is false (4) Both (A) and (R) are true but (R) is NOT the correct explanation of (A)

1. Both (A) and (R) are true and (R) is the correct explanation of (A)
2. (A) is false but (R) is true
3. (A) is true but (R) is false
4. Both (A) and (R) are true but (R) is NOT the correct explanation of (A)

Correct answer: Both (A) and (R) are true and (R) is the correct explanation of (A)

Solution

Both statements are accurate; NH3 has a greater dipole moment due to the lone pair's contribution aligning with the N-H bonds, while NF3's dipole moment is reduced because the highly electronegative fluorine atoms create a dipole that opposes the lone pair's effect.

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