Question

Assertion $N _{3}^{-}$is a weaker base than $NH _{2}^{-}$.
Reason The lone pair of electrons on $N$ atom in $N _{3}^{-}$is in a $s p^{2}$-orbital while in $NH _{2}^{-}$it is in an $s p^{3}$-orbital.

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

Answer 1

Answer: (A)

Basicity depends upon availability of lone pair of electrons. Since $N _{3}^{-}$is in $s p^{2}$-orbital, its lone pair is less available as compared to $NH _{2}^{-}$which is in $NH _{2}^{-}$. Thus, $N _{3}^{-}$is a weaker base than $NH _{2}^{-}$. Hence, Reason is the correct explanation of Assertion.