$A$ solution of a substance $X$ is used for whitewashing.
$(i)$ Name the substance $X$ and write its formula.
$(ii)$ Write the reaction of the substance $X$ named in $(i)$ above with water.

What is the difference between displacement and double displacement reactions? Write equations for these reactions.

Oil and fat containing food items are flushed with nitrogen. Why?

Write the balanced chemical equations for the following reactions.
$(a)$ Calcium hydroxide $+$ Carbon dioxide $\rightarrow$ Calcium carbonate $+$ Water
$(b)$ Zinc $+$ Silver nitrate $\rightarrow$ Zinc nitrate $+$ Silver
$(c)$ Aluminium $+$ Copper chloride $\rightarrow$ Aluminium chloride $+$ Copper
$(d)$ Barium chloride $+$ Potassium sulphate $\rightarrow$ Barium sulphate $+$ Potassium chloride

What do you mean by a precipitation reaction? Explain by giving examples.

Explain the term 'Corrosion' with one example.