Arrange in decreasing order of acidity: CH₃COOH, CH₂ClCOOH, CH₃CH₂CH₂COOH.
Acidity increases with electron-withdrawing groups: CH₂ClCOOH (Cl) > CH₃COOH > CH₃CH₂CH₂COOH (alkyl reduces acidity).
Ref: NCERT Class 12 Chemistry > Chapter 12: Aldehydes, Ketones and Carboxylic Acids > Topic: Chemical Reactions - Reduction, Oxidation and Tests - Tollens, Fehling, Iodoform