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.