Statement I: CH3NH2 is more basic than NH3 but C6H5NH2 is less basic than NH3. Explanation: Methylamine (CH3NH2) : The −CH3 group is electron donating ( + I effect), which increases the electron density on nitrogen, making it more basic than ammonia. Aniline ( C6H5NH2 ): The lone pair on nitrogen gets delocalized into the benzene ring through resonance, reducing its availability to accept a proton. So aniline is less basic than ammonia. Hence, Statement I is correct.
Statement II: The order of basic strength of amines in aqueous phase follows the order (C2H5)3N>(C2H5)2NH>C2H5NH2. Let's check this: In the aqueous phase, basic strength is influenced by two factors: + I effect (electron donating alkyl groups increase basicity) Solvation effect (stabilization of the conjugate ammonium ion) In aqueous solution, the solvation effect is strong for primary > secondary > tertiary amines, because primary amines can form more hydrogen bonds. However, the +1 effect increases as we move from primary ⟶ secondary ⟶ tertiary. The combined effect in aqueous phase gives the observed order: Secondary amine > Primary amine > Tertiary amine That is: (C2H5)2NH>C2H5NH2>(C2H5)3N But the statement says the order is: (C2H5)3N>(C2H5)2NH>C2H5NH2 This is incorrect in aqueous medium.
