For the elements sodium and phosphorous, state the following

(a) the formula of the chloride of each element,

(b) the physical state of each chloride at room temperature (i.e., solid, liquid or gas), and

(c) the nature of bonding of each chloride (i.e., ionic or covalent)

Describe the two colour changes that take place when moist blue litmus is placed in a gas jar of chlorine. What are these colour changes that take place when chlorine water is exposed to sunlight?

In each case, describe one chemical test applied to the following substances, which would enable you to distinguish between them : carbon dioxide gas and hydrogen chloride gas

Give reasons for : 'It is dangerous to sleep in a closed room in which a coal fire is burning'.