The correct answer is D. its aqueous solution turns red litmus blue.
Ammonia is a colorless gas with a characteristic pungent odor. It is highly soluble in water, and its aqueous solution is basic, turning red litmus blue. Ammonia is a very important industrial chemical, and it is also used in household products such as cleaners and fertilizers.
Option A is incorrect because ammonia is highly soluble in water.
Option B is incorrect because ammonia has a characteristic pungent odor.
Option C is incorrect because ammonia is a colorless gas.