Question

Which of the following is NOT a chemical change?

• A. Digestion of food
• B. Precipitation of rain and snow
• C. Rusting of iron
• D. Burning of paper

Answer 1

Answer: (B)

Precipitation is any product of the condensation of atmospheric water vapour that falls under gravity. The main forms of precipitation include drizzle, rain, sleet, and snow.

Precipitation occurs when a portion of the atmosphere becomes saturated with water vapour so that the water condenses and "precipitates". Here the water vapour in the air is changing from one form to another.

So precipitation of snow and rain is not a chemical change. In all the other options, a new substance is formed and the main substances cannot be reversed. So, they are chemical changes.