The correct order of acidity for the following compounds is

Options

A. `I gt II gt III gt IV`
B. `III gt I gt II gt IV`
C. `III gt IV gt II gt I`
D. `I gt III gt IV gt II`

Answer

A

Explanation

Due to artho-effect, (I) and (II) are stronger acid than (III) and (IV). Due to two ortho hydroxyl groups in (I), it is stronger acid than (II). (III) is a stronger acid than (IV) because at m-position, -OH group cannot exert its +R effect but can only exert its -I effect while at p-position, -OH group exerts its strong +R effect. Thus, the correct order of acidity is : I gt II gt III gt IV.