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

Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it,as shown in the figure below.
$(a)$ What will be the action of the gas on
$(i)$ dry litmus paper?
$(ii)$ moist litmus paper?
$(b)$ Write a balanced chemical equation for the reaction taking place.

Give reasons: Aluminium is a highly reactive metal,yet it is used to make utensils for cooking.

Why is sodium kept immersed in kerosene oil?

Food cans are coated with tin and not with zinc because

Which gas is produced when dilute hydrochloric acid is added to a reactive metal? Write the chemical reaction when iron reacts with dilute $H_2SO_4$.