MCQ
Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.

Assertion $(A)$ : $\mathrm{NH}_3$ and $\mathrm{NF}_3$ molecule have pyramidal shape with a lone pair of electrons on nitrogen atom. The resultant dipole moment of $\mathrm{NH}_3$ is greater than that of $\mathrm{NF}_3$.

Reason $(R)$ : In $\mathrm{NH}_3$, the orbital dipole due to lone pair is in the same direction as the resultant dipole moment of the $\mathrm{N}-\mathrm{H}$ bonds. $\mathrm{F}$ is the most electronegative element.

In the light of the above statements, choose the correct answer from the options given below:

  • Both $(A)$ and $(R)$ are true and $(R)$ is the correct explanation of $(A)$
  • B
    $(A)$ is false but $(R)$ is true
  • C
    $(A)$ is true but $(R)$ is false
  • D
    Both $(A)$ and $(R)$ are true but $(R)$ is NOT the correct explanation of $(A)$

Answer

Correct option: A.
Both $(A)$ and $(R)$ are true and $(R)$ is the correct explanation of $(A)$
a
Resultant dipole moment $=0.80 \times 10^{-30} \mathrm{Cm}$

(Image)

Resultant dipole moment $=4.90 \times 10^{-30} \mathrm{~cm}$

(Image)

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free