JEE MainChemistryGeneral Organic Chemistry
Consider the following compounds: (A) CH ₃- CO - CH ₂- CO - CH ₃ (B) CH ₃- CO - CH ₂- COOC ₂ H ₅ (C) C ₂ H ₅ OOC - CH ₂- COOC ₂ H ₅ (D) CH ₃- CO - CH ₃ The correct decreasing order of p K_a values for the most acidic protons in these compounds is:
Options
- AA > B > C > D
- BD > A > B > C
- CD > C > B > A
- DD > B > C > A
Correct answer
C. D > C > B > A
Step-by-step solution
The p K_a value of an acid is inversely proportional to its acidic strength. A weaker acid has a higher p K_a value. The acidity of the given compounds depends on the stability of the carbanion formed after the removal of the most acidic proton. The stability of the carbanion is determined by the electron-withdrawing ability of the adjacent groups. Compound (D) has only one carbonyl group, making its carbanion the least stable and the compound the least acidic (highest p K_a ). Compounds (A), (B), and (C) have acti