The sketch illustrates refining of aluminium by Hoope's process. [reference]

(i) Which of A and B is the cathode and which one is the anode?

(ii) What is the electrolyte in the tank?

(iii) What material is used for the cathode?

The following is a sketch of an electrolytic cell used in the extraction of aluminium :

(i) What is the substance of which the electrodes A and B are made?

(ii) At which electrode (A or B) is the aluminium formed ?

(iii) What are the two aluminium compounds in the electrolyte C ?

(iv) Why is it necessary for electrode B to be continuously replaced ?

The metal oxide which can react with acid as well as alkali is :

1. Silver oxide
2. Copper [II] oxide
3. Aluminium oxide
4. Calcium oxide

State the property of the metal utilized in Aluminium in Thermite welding.