Structural formula of a cyclic compound is given.

Write down the molecular formula of this compound.

Various allotropes of carbon are given in the box.

a) What is meant by Allotropy?

b) Which are the crystalline allotropes of carbon among those given above?

c) Mention one use of any of these crystalline allotropes.

Certain uses of graphite are given. Identify the characteristics of it made use of here.

a) Used to make pencil lead.

b) Used as a solid lubricant.

When carbon reacts with oxygen , carbon dioxide gas is produced.

a) Which is the gas obtained on either increasing the amount of carbon or decreasing the amount of oxygen in the above process?

b) It is dangerous to inhale the gas thus formed. Give reason.

c) Mention any use of this gas?

When carbon and carbon compounds burn in oxygen CO₂ is produced.

a) Specify an activity in which plants make use of ‍ CO₂ gas ?

b) Mention any one use of CO₂ .

c) Name the solid form of CO₂ ? Mention any use of it?

Carbon dioxide is a compound of carbon present in the atmosphere.

a) What is the consequence of the tremendous increase in the amount of CO₂ in the atmosphere?

b) Write down an activity that increases the amount of CO₂ in the atmosphere.

Two uses of diamond are given below. Identify the characteristics of diamond made use of here.

a) Used to make ornaments.

b) Used for cutting glass.

The characteristics of diamond and graphite, the crystalline allotropes of carbon are given.

Classify them and fill up the table given below.

1. Conducts electricity

2. transparent

3. used as a lubricant

4. does not conduct electricity