Reactions of ammonium chloride

Steps:

• NH4Cl dissociates in water to NH4+ and Cl- ions, enabling specific reactions.
• Evaluate A: Test for NH4+ with base, but condition "hot aqueous" is standard for gas evolution.
• Evaluate B: Test for Cl- with Ag+, forming insoluble product.
• Evaluate C: Reaction with conc H2SO4 yields HCl gas, not Cl2; D lacks details.

Why B is correct:

• In solution, Cl- reacts with AgNO3 per Ag+ + Cl- → AgCl (white precipitate), a standard qualitative test for chloride ions.

Why the others are wrong:

• A: Incorrect; ammonia gas evolves only when the mixture of NH4Cl and NaOH solution is heated, not specifically from "hot aqueous" NaOH alone.
• C: Incorrect; solid NH4Cl + conc H2SO4 → NH4HSO4 + HCl gas, no chlorine produced.
• D: Not enough information.

Final answer: B