Which statement describes ammonia gas?

• A. Colourless with a pungent smell
• B. Colourless with odourless
• C. Green with a pungent smell
• D. Purple and odourless

Answer: (A)

Ammonia gas is colorless and has a sharp, pungent odor. That combination makes the statement describing it as colorless with a pungent smell correct. The other descriptions are not true for ammonia: it is not odorless, it is not colored (no green or purple tint in typical gas), so those options don’t match what ammonia actually is. The noticeable smell also helps people detect leaks, which is useful in practical settings.