Question

Rank the following compounds in order of increasing acidity.

Question options:

	1 < 4 < 2 < 3
	4 < 2 < 1 < 3
	3 < 4 < 2 < 1
	3 < 2 < 4 < 1
	3 < 1 < 4 < 2

Answer 1

strength of acid depends on stability of conjugate base

COOH is more acidic than OH since COO- is more stable than O- .

Now we had three molecules having COOH . The molecule whose COO- is most stabilised among three is most acidic . Electronw ithdrawing groups stabilise negative charge . Hence molecule 2 which has Cl nearer COO- stabilises COO- more and is most acidic. Next is 4, next is 1 and finally 2 is least acidic

Order of acidity is    3 < 1 < 4 < 2