The most important condition for resonanace to occur is that the invovled atoms in resonating structure must be coplanar or nearly coplanar for maximum delocalisation. If this condition does not fulfil, involved orbitals cannot be parallel to each other and as consequence delocalisation cannot occur. Bulky groups present on adjacent atoms inhibit the planarity of atoms involved in resonance. this pehnomenon is known as steric inhibition of resonance. Steric inhibition of resonance has profound effect on
Q. Which of the following is most acidic:
A.
B.
C.
D.
