Properties and Preparation of Ammonia

Steps:

• Recall ammonia (NH₃) is a colorless gas with pungent odor, basic in nature.
• Check physical properties: not odorless, turns damp red litmus blue.
• Evaluate production methods: lab prep involves reducing nitrates with NaOH and Al; industrial uses Fe catalyst.
• Eliminate incorrect options by matching to known facts.

Why C is correct:

• Ammonia forms via reduction of nitrate ion: KNO₃ + NaOH + Al → NH₃ (gas) + byproducts, a standard lab method using aluminum as reducing agent.

Why the others are wrong:

• A: Ammonia has a strong pungent odor, not odorless.
• B: As a base, ammonia turns damp red litmus blue, not red.
• D: Haber-Bosch process for ammonia uses iron catalyst; V₂O₅ is for SO₂ to SO₃ in sulfuric acid production.

Final answer: C