Acidity order and derivative reactivity among drawn carboxylic acids

14 questions on Acidity order and derivative reactivity among drawn carboxylic acids from the Aldehydes, Ketones and Carboxylic Acids chapter: 2 NEET level, 5 JEE Main, 7 JEE Advanced. Each one opens with its answer and solution.

• The acid shown has pK_a = 4.76. Which of the structures A to D is the strongest acid? NEET level, drawn structure
• The compound shown is compared with an anhydride, an ester and an amide of the same acyl group. Which order of reactivity toward nucleophilic acyl substitution ... JEE Main level, drawn structure
• The acid shown has pK_a = 4.06. Which of the structures A to D is expected to have the lowest pK_a? JEE Main level, drawn structure
• The acid shown has pK_a = 4.47, while benzoic acid has pK_a = 4.20. The best explanation is JEE Main level, drawn structure
• The acid shown has pK_a = 2.17 whereas its para isomer has pK_a = 3.44. The main reason for the greater acidity of the drawn acid is JEE Main level, drawn structure
• Which hydrogen of the molecule shown is the most acidic? NEET level, drawn structure
• The acid shown is heated with excess ethanol and a few drops of conc. H2SO4 (Fischer esterification). Which structure is the major organic product? JEE Main level, drawn structure
• The acid shown is heated with methanol enriched in ^18O (CH3-18OH) and a catalytic amount of H2SO4. Which structure is the ester that forms? JEE Advanced level, drawn structure
• The beta-keto acid shown is heated gently, and the neutral product is then treated with excess I2/NaOH. Which statements are correct? JEE Advanced level, drawn structure
• The diacid shown is heated at about 150 degC until CO2 evolution stops, and the product is treated with Br2/red P followed by water. Which structure is the fina... JEE Advanced level, drawn structure
• The anhydride shown reacts with nucleophiles. Which statements are correct? JEE Advanced level, drawn structure
• The acid shown has pK_a = 4.37 (benzoic acid 4.20; 4-nitrobenzoic acid 3.44; 4-methoxybenzoic acid 4.47). Which statements are correct? JEE Advanced level, drawn structure
• The hydroxy acid shown is warmed with a catalytic amount of acid. Which statements are correct? JEE Advanced level, drawn structure
• The anhydride shown is first warmed with one equivalent of methanol (no catalyst), and the product is then refluxed with excess ethanol and conc. H2SO4. Which s... JEE Advanced level, drawn structure