When potassium iodide solution is added to a solution of lead $(II)$ nitrate in a test tube,a precipitate is formed.
$(i)$ What is the colour of this precipitate?
$(ii)$ Name the compound precipitated.

Name the oxidising and reducing agent in the following reaction:
$CuO + H_{2} \longrightarrow Cu + H_{2}O$

When hydrogen gas burns in the presence of oxygen,water is formed,and when water is electrolysed,hydrogen and oxygen gases are produced. State the kind of reaction that takes place:
$(a)$ In the first case
$(b)$ In the second case

$A, B$ and $C$ are three elements which undergo chemical reactions according to the following equations:
$A_{2}O_{3} + 2B \rightarrow B_{2}O_{3} + 2A$
$3CSO_{4} + 2B \rightarrow B_{2}(SO_{4})_{3} + 3C$
$3CO + 2A \rightarrow A_{2}O_{3} + 3C$
Answer the following questions with reasons:
$(a)$ Which element is the most reactive?
$(b)$ Which element is the least reactive?
$(c)$ What is the type of reactions listed above?

Translate the following statement into a chemical equation and balance it:
$(a)$ Aluminium chloride reacts with ammonium hydroxide to form a gelatinous white precipitate of aluminium hydroxide and a salt of ammonium chloride.

What happens when a piece of $Zn$ metal is added to $CuSO_4$ solution?