The decreasing order of the `pK_a` values of the following compounds is:

Options

A. B > C > D > A
B. C > B > A > D
C. D > A > C > B
D. B > C > A > D

Answer

C

Explanation

More the acidic strength lesser will be the value of `pK_a`
is most acidic as it’s conjugate base is resonance stabilized by `NO_2` group Overall order of acidic strength

Conjugate base is destabilized by +M of –OMe, hence least acidic. Decreasing Order of pKa D > A > C > B