The correct order of decreasing basic strength for the following amines is: (i) C ₆ H ₅ NH ₂ (ii) C ₆ H ₅ CH ₂ NH ₂ (iii) ( C ₆ H ₅)₂ NH (iv) C ₆ H ₁₁ NH ₂

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 cyclohexylamine (iv), the lone pair on nitrogen is localized and the cyclohexyl group exerts a +I effect, increasing electron density on nitrogen. It is the most basic. In benzylamine (ii), the - NH ₂ group is attached to an sp^3 hybridized carbon, so the lone pair is localized. However, the phenyl group exerts a -I effect, making it slightly less basic than cyclohexylamine. In aniline (i), th