Arrange the following compounds in the decreasing order of their acidic strength: (I) (II) (III)

Step-by-step solution

The acidic strength of substituted benzoic acids depends on the stability of the conjugate base (carboxylate anion). Electron-withdrawing groups (EWG) stabilize the anion through -R and -I effects, increasing acidity. Electron-donating groups (EDG) destabilize the anion through +R , +H , or +I effects, decreasing acidity. In compound (I), the - NO ₂ group is a strong EWG showing both -R and -I effects. In compound (II), the - CN group is also an EWG showing -R and -I effects, but its electron-withdrawing power is l