Name the most common ore of the metal aluminium from which the metal is extracted. Write the chemical formula of the ore.

Choose the correct answer from the options A, B, C and D given. The reason for using aluminium in the alloy duralumin is:

A: Aluminium is brittle
B: Aluminium gives strength
C: Aluminium brings lightness
D: Aluminium lowers melting point

Name the main component of the alloy -

(i) Brass

(ii) Duralumin

Write a balanced chemical equation for -

(i) The formation of aluminium at the cathode, during the electrolysis of alumina

(ii) Action of heat on aluminium hydroxide.