question_answer

Give the decreasing order of \[{{K}_{a}}\] value of the following compounds.

(I)

(II)

(III)

(IV)

A) \[I>IV>III>II\]

B)        \[II>III>IV>I\]

C) \[I>III>II>IV\]

D)        \[I>IV>II>III\]

Correct Answer: A

Solution :

[a]  Therefore, the order of acidic character: Aromatic > Non-aromatic > Anti-aromatic. But anti-aromaticity of (III) is more than (II) since (III) is more resonance stabilised than (II). Therefore, the order of decreasing acidic character or \[{{K}_{a}}\]value is (I) > (IV) > (III) > (II)