Which one of the following compounds possesses the most acidic hydrogen?
Question:

Which one of the following compounds possesses the most acidic hydrogen?

Correct Option: , 4

Solution:

Acidic strength $\propto-\mathrm{I},-\mathrm{M}$ effect. Due to strong $-\mathrm{I}$, and $-\mathrm{M}$ effect of $3-\mathrm{COOCH}_{3}$ group, it has most acidic Hydrogen.