MHT CET Chemistry Question (2026) — Solution

Step-by-step solution

Basic strength of amines depends on the availability of the lone pair of electrons on the nitrogen atom for protonation. In aliphatic amines, the electron-donating +I effect of alkyl groups increases the electron density on nitrogen, making them more basic than ammonia. For methylamines in aqueous solution, the combined effect of the +I effect, steric hindrance, and hydration energy results in the basic strength order: secondary > primary > tertiary. Thus, ( CH _3)_2 NH > CH _3 NH _2 > NH _3. In aniline ( C _6 H _5 NH _2), the lone pair of electrons on the nitrogen atom is delocalized over the benzene ring due to resonance. This decreases the availability of the lone pair for protonation, making aniline less basic than ammonia. Combining these factors, the correct decreasing order of basic strength is ( CH _3)_2 NH > CH _3 NH _2 > NH _3 > C _6 H _5 NH _2. Answer: ( CH _3)_2 NH > CH _3 NH _2 > NH _3 > C _6 H _5 NH _2