Suggest two ways to check the rancidity of food. 

Solid calcium oxide was taken in container and water was added slowly to it.

Write the observation.

Solid calcium oxide was taken in container and water was added slowly to it.

Write the chemical formula of the products obtained.

Describe an activity to show that the combination reaction between quicklime and water is an exothermic reaction. 

Identify the substance oxidised & the substance reduced in the given chemical equation.

${\mathrm{MnO}}_2\left(\mathrm{s}\right) +4\mathrm{HCl}\left(\mathrm{conc}.\right) \to {\mathrm{MnCl}}_2\left(\mathrm{aq}\right) +{\mathrm{Cl}}_2\left(\mathrm{g}\right) +2{\mathrm{H}}_2\mathrm{O}$

Explain which is the reducing agent & oxidising agent.

Give an example of the following.

A reaction which is a double displacement as well as a precipitation reaction.

Give an example of the following.

A Redox reaction.