State whether the following statement is true or false:
The elements or compounds,which occur naturally in the earth's crust,are known as minerals.

What is the chemical formula of bauxite?

$(a)$ Consider the following chemical equation:
$Fe_{2}O_{3} + 2Al \rightarrow Al_{2}O_{3} + 2Fe$
Name two categories in which you can place this reaction.
$(b)$ Define the term 'Oxidation' of a substance and name the substance oxidised and the oxidising agent in the above reaction.

Two ores $A$ and $B$ were taken. On heating, ore $A$ gives $CO_2$, whereas ore $B$ gives $SO_2$. What steps will you take to convert them into metals?

Which of the following metals is used for making jewelry?

Which of the following properties is generally not shown by metals?