Write any two observations in an activity which may suggest that a che

1.	Write any two observations in an activity which may suggest that a chemical reaction has taken place. Give an example in support of your answer.
Answer» 1. Evolution of gas. For example: When sodium carbonate reacts with dilute hydrochloric acid, carbon dioxide gas is evolved. 2. Formation of a precipitate. For example: When potassium iodide solution is added to a solution of lead nitrate, yellow precipitate of lead iodide is formed.

Write any two observations in an activity which may suggest that a chemical reaction has taken place. Give an example in support of your answer.

Answer»

1. Evolution of gas.

For example: When sodium carbonate reacts with dilute hydrochloric acid, carbon dioxide gas is evolved.

2. Formation of a precipitate.

For example: When potassium iodide solution is added to a solution of lead nitrate, yellow precipitate of lead iodide is formed.