In the electrolytic refining of a metal M, what would you take as the anode, the cathode and the electrolyte?

Pratyush took sulphur powder on spatula and heated it. He collected the gas evolved by inverting a test tube over it as shown below :

(a) What will be the action of gas on

(i) dry litmus paper?

(ii) moist litmus paper?

(b) Write a balanced chemical equation for the reaction taking place.

What types of oxides are formed when non-metals combine with oxygen?

Give reasons :

(a) Platinum, gold and silver are used to make jewellery.

(b) Sodium, potassium and lithium are stored under oil.

(c) Aluminium is highly reactive metal, yet it is used to make utensils for cooking.

(d) Carbonate and sulphides ores are usually converted into oxides during the process of extraction.