(a) Mayank extracts aluminium by electrolytic process. Answer the following questions with respect to the electrolytic process in the extraction of aluminium.

(1) A compound which is added to lower the fusion temperature of the electrolytic bath.

(2) Explain, why powdered coke is sprinkled over the electrolytic mixture?

(b) The atomic number of an element is 16. To which group will this element belong to?

The following is a list of methods for the preparation of salts:

A — direct combination of two elements

B — reaction of a dilute acid with a metal

C — reaction of a dilute acid with an insoluble base

D — titration of a dilute acid with a solution of soluble base.

E — reaction of two solutions of salts to form a precipitate.

Choose from the list A to E, the best method of preparing the following salts by giving a suitable equation in each case:

1. Copper (II) Sulphate
2. Calcium Carbonate
3. Zinc sulphate

Distinguish between the following as directed.

(a) Ammonium chloride and sodium chloride on the basis of heating

(b) Ferric salt and ferrous salt by using ammonium hydroxide

Name the ions present in each of the following

(a) NaCl

(b) CH₃COOH

(c) H₂O