Q. Guanidine, $\left( NH _{2}\right)_{2} C = NH$, is said to be the strongest nitrogen containing organic base because:
Amines
Solution:
On the basis of hybridisation, $N \left(s p^{3}\right)$ of $NH _{2}$ with less $s$ character should be more basic than $N \left(s p^{2}\right)$ of the aimino $(= NH )$ group. However, $N$ of imino group is more basic and it is this nitrogen which is protonated because its conjugate acid is resonance hybrid of three equivalent structure which accounts its unusual stability.
