Write the chemical equation of the reaction with an example in which a change in colour takes place.

When sulfur dioxide gas is passed through lime water,which insoluble substance is formed that turns the solution milky?

Why is the amount of gas collected in one of the test tubes in the image double the amount collected in the other? Name this gas.

State the kind of chemical reactions in the following examples:
$(a)$ Digestion of food in the stomach
$(b)$ Combustion of coal in air.

The following reaction is used for the preparation of oxygen gas in the laboratory:
$2KClO_{3(s)} \xrightarrow[Catalyst]{Heat} 2KCl_{(s)} + 3O_{2(g)}$
Which of the following statement$(s)$ is(are) correct about the reaction?

Write one example for each of the decomposition reactions carried out with the help of:
$(i)$ electricity
$(ii)$ heat
$(iii)$ sunlight
Give balanced chemical equations in each case.