Which process is used to obtain metal from metal oxide?

An element $A$ burns with a golden yellow flame in air. It reacts with another element $B$ (atomic number $17$) to give a product $C$. An aqueous solution of product $C$ on electrolysis gives a compound $D$ and liberates hydrogen. Identify $A$,$B$,$C$,and $D$. Also,write down the equations for the reactions involved.

An electrolytic cell consists of
$(i)$ positively charged cathode
$(ii)$ negatively charged anode
$(iii)$ positively charged anode
$(iv)$ negatively charged cathode

Why are sulphide and carbonate ores converted into oxides?

Why do ionic compounds have high melting points? State the reason.

Electrical wires have a coating of an insulating material. The material generally used is