Which of the following is NOT a form of precipitation in chemical reactions?

• A. Production of an insoluble compound in water
• B. Evolution of a gas during a reaction
• C. Formation of a solid from two aqueous solutions
• D. Appearance of a cloudy suspension in a solution

Answer: (B)

Verified step by step guidance

1. Understand that precipitation in chemical reactions refers to the formation of a solid (precipitate) when two aqueous solutions react and produce an insoluble compound.
2. Identify that 'Production of an insoluble compound in water' describes the formation of a precipitate, which is a classic example of precipitation.
3. Recognize that 'Formation of a solid from two aqueous solutions' also describes precipitation, as it involves the creation of a solid from dissolved ions.
4. Note that 'Appearance of a cloudy suspension in a solution' indicates the presence of tiny solid particles suspended in the liquid, which is consistent with precipitation.
5. Realize that 'Evolution of a gas during a reaction' is not a form of precipitation because it involves the release of a gas, not the formation of a solid precipitate.