Aluminium is a quite reactive metal according to its position in the activity series, yet it is used for making window frames and cooking utensils. Explain why? 

Explain with reasons: 

In the electrolytic reduction of alumina, the graphite anode is gradually consumed. 

Explain with reasons: 

Roasting is carried out on sulphide ores and not on carbonate ores. 

Explain with reasons:

Carbon can reduce lead oxide but not aluminium oxide. 

For the substance listed below, explain its significance in the extraction of aluminium.

Bauxite.

For the substance listed below, explain its significance in the extraction of aluminium.

Cryolite. 

For the substance listed below, explain its significance in the extraction of aluminium.

Sodium hydroxide. 

For the substance listed below, explain its significance in the extraction of aluminium.

Graphite. 

Write the balanced equation for the following reaction: 

Reduction of copper oxide by hydrogen.