Fundamentals of Organic ChemistryChemistryAmines
Identify the correct increasing order of basic strength for the following compounds: (i) (ii) (iii) (iv) CH ₃ CN
Options
- A(iv) < (ii) < (iii) < (i)
- B(iv) < (iii) < (i) < (ii)
- C(iv) < (i) < (iii) < (ii)
- D(iv) < (iii) < (ii) < (i)
Correct answer
B. (iv) < (iii) < (i) < (ii)
Step-by-step solution
The basic strength of nitrogenous compounds depends on the availability of the lone pair of electrons on the nitrogen atom for protonation. This availability is influenced by the hybridization of the nitrogen atom and whether the lone pair is involved in resonance or aromaticity. In piperidine (ii), the nitrogen atom is sp^3 hybridized. The lone pair is localized in an sp^3 orbital and is readily available for protonation, making it the most basic among the given compounds. In pyridine (i), the nitrogen atom is sp^