Fundamentals of Organic ChemistryChemistryGeneral Organic Chemistry
Identify the correct increasing order of acidity for the following compounds: (i) CH ₃ CH ₂ CH ₂ CO ₂ H (ii) CH ₃ CH ₂ CH ( Cl ) CO ₂ H (iii) CH ₃ CH ₂ CH ₂ CH ₂ OH
Options
- A(ii) < (i) < (iii)
- B(ii) < (iii) < (i)
- C(i) < (ii) < (iii)
- D(iii) < (i) < (ii)
Correct answer
D. (iii) < (i) < (ii)
Step-by-step solution
Compound (iii) is an alcohol, while (i) and (ii) are carboxylic acids. Carboxylic acids are significantly more acidic than alcohols due to the resonance stabilization of the carboxylate ion. Thus, (iii) is the least acidic. Between the two carboxylic acids, compound (ii) has an electronegative chlorine atom at the -position. The -I effect of the chlorine atom withdraws electron density, stabilizing the conjugate base and thereby increasing the acidity compared to the unsubstituted carboxylic acid (i). Therefore, th