Question

Assertion : $BF_3$ molecule is planar but $NF_3$ is pyramidal.
Reason : N atom is smaller than B.

• A. Both Assertion and Reason are true and Reason is the correct explanation of Assertion
• B. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion
• C. Assertion is true but Reason is false
• D. Both Assertion and Reason are false

Answer 1

Answer: (B)

In $BF _{3}$, boron is $s p^{2}$ -hybridised, so it is trigonal planar. In $NF _{3}$, nitrogen is $sp ^{3}$ -hybridised. But due to the presence of one lone pair it becomes pyramidal from tetrahedral.