The increasing order of pK a for the following phenols is (A) 2,4-Dinitrophenol (B) 4-Nitrophenol (C) 2,4…

The increasing order of pKa for the following phenols is

(A) 2,4-Dinitrophenol

(B) 4-Nitrophenol

(C) 2,4,5-Trimethylphenol

(D) Phenol

(E) 3-Chlorophenol

Choose the correct answer from the option given below :

  1. (A), (E), (B), (D), (C)
  2. (A), (B), (E), (D), (C)
  3. (C), (D), (E), (B), (A)
  4. (C), (E), (D), (B), (A)

Solution

Order of acidity for following phenol is

Increasing order of pKa means most acidic will be placed first. 

- M groups at ortho and para position increases acidic strength in phenol. Hence, (A) is most acidic.

+M, Hyperconjugation, +I decreases Ka Value of 2,4,5-Trimethylphenol. Hence (C), is least acidity.

So, the order of pKa value is (A) < (B )< (E)< (D)< (C).

Asked in: JEE Main 2023 (29 Jan Shift 1)

Practice more Alcohols Phenols and Ethers questions on Aicharya