COMEDK 2025 Afternoon Solved Paper

Concept:Understanding the properties, preparation, and uses of important halogen compounds.Explanation:• Option A: $\mathrm{CH}_{2}\mathrm{Cl}_{2}$ (dichloromethane) is used both as a solvent and sometimes as a propellant in aerosols. Hence the statement is correct.• Option B: DDT was widely employed because it effectively killed mosquitoes that transmit malaria. This statement is correct.• Option C: Freon‑12 ($\mathrm{CCl}_{2}\mathrm{F}_{2}$) is prepared from carbon tetrachloride ($\mathrm{CCl}_{4}$) by the Swarts reaction, not from trichloromethane ($\mathrm{CHCl}_{3}$). The reaction is: $$\mathrm{CCl}_{4} + 2\,\mathrm{HF}\xrightarrow{\mathrm{SbCl}_{5}}\mathrm{CCl}_{2}\mathrm{F}_{2} + 2\,\mathrm{HCl}$$ Therefore the statement in option C is false.• Option D: Iodoform slowly liberates iodine ($\mathrm{I}_{2}$) when it contacts skin, providing its antiseptic action. This statement is correct.Answer:Option C is the incorrect statement.