Question

Assertion $N_3^{-}$is a weaker base than $N{H}_2^{-}$.
Reason The lone pair of electrons on $N$ atom in $N_3^{-}$is in a $s{p}^2$-orbital while in $N{H}_2^{-}$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 $N{H}_2^{-}$which is in $N{H}_2^{-}$. Thus, $N_3^{-}$is a weaker base than $N{H}_2^{-}$. Hence, Reason is the correct explanation of Assertion.