Question

A student performs the following experiment in his school laboratory. List two observations to justify that in this experiment a chemical change has taken place.

Select from the following a decomposition reaction in which source of energy for decomposition is light :

Name the type of chemical reaction in which calcium oxide reacts with water. Justify your answer by giving balanced chemical equation for the chemical reaction.

Write one chemical equation each for the chemical reaction in which the following have taken place : (i) Change in colour (ii) Change in temperature (iii) Formation of precipitate Mention colour change/temperature change (rise/fall)/compound precipitated along with equation.