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 Reason is the correct explanation of Assertion.
• B. If both Assertion and Reason are true but Reason is not the correct explanation of 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 $ \text{N}_{3}^{-} $ is in $ s{{p}^{2}}- $ orbital, its lone pair is less available as compared to $ NH_{2}^{-} $ in which the lone pair is in $ s{{p}^{3}} $ orbital. Thus, $ N_{3}^{-} $ is a weaker base than $ NH_{2}^{-}. $