Question

Q. 4] Solve any one from the following questions

1] Read the following paragraph and answer the

questions based on it. 5

The phenomenon of existence of a substance in

various physical forms but the same chemical form is

known as allotropy. Both diamond and graphite are

formed by carbon atoms. Diamond is a hard,

beautiful crystalline substance while graphite is a

soft, grayish black crystalline substance. In diamond,

each carbon atom is linked to four other

neighbouring carbon atoms held the corners of aregular tetrahedron by covalent bonds to form a

rigid three dimensional structure. In case of graphite,

each carbon atom is attached to three other carbon

atoms forming a hexagonal planar structure. Physical

properties of graphite and diamond are different but

their chemical properties are the same. In diamond,

there are no mobile electrons in the system and hence

a diamond crystal is a non-conductor of electricity.

On the other hand, in graphite, free electrons move

throughout the entire layers and hence graphite is a

good conductor of electricity.

Uses : Diamond is used as a precious stone in

jewellery. Black diamonds are used for cutting glass,

while graphite is used in making electrodes and

carbon, lubricants and lead pencils.

i) What is allotropy?

ii) Name the allotrope of carbon which conduct

electricity?

iii) Name the soft, brittle allotrope of carbon.

iv) Which allotrope of carbon is used to cut glass?

v) Name the allotrope of carbon which has regular

tetrahedron, three dimensional structure.
​

Answer 1

Answer:

1)The phenomenon of existence of a substance in various physical forms but the same chemical form is known as allotropy.

2)GRAPHITE

3)GRAPHITE

4) DIAMOND

5) DIAMOND