The chemical formula of argentite is ${\mathrm{Ag}}_{\mathrm{k}}\mathrm{S}$. Here, the value of $\mathrm{k}$ is 

Name the following:

A metal extracted from bauxite ore.

Fill in the blank with the correct choice given in the bracket - The most common ore of iron is _____.

Most of the metals that we require are obtained from their ores by reduction:

Name the ore of the zinc metal obtained by chemical reduction.

Name the following:

An ore of zinc containing its sulphide.

Name the following:

The ore of zinc containing its sulphide.

Arrange the metal oxides given below according to the activity series. (Place the metal oxide which is most difficult to reduce first.)

Aluminium oxide, copper oxide, iron(III) oxide and magnesium oxide.