English Medium Class 10 - CBSE Question Bank Solutions for Science

State one use of diamond which depends on its 'extraordinary brilliance' and one use of graphite which depends on its being 'black and quite soft'.

What is diamond? Of what substance is diamond made?

Describe the structure of diamond. Draw a simple diagram to show the arrangement of carbon atoms in diamond.

Explain why, diamond has a high melting point.

State any two uses of diamond.

 What is graphite?

what substance is graphite made?

Describe the structure of graphite with the help of a labelled diagram.

Why is graphite a good conductor of electricity but diamond is a non-conductor of electricity?

State any two uses of graphite.

Why are covalent compounds generally poor conductors of electricity?

The atomic numbers of four elements P, Q, R and S are 6, 10, 12 and 17 respectively. Which two elements can combine to form a covalent compound?
(a) P and R
(b) Q and S
(c) P and S
(d) R and S

The solution of one of the following compounds will not conduct electricity. This compounds is:
(a) NaCl
(b) CCl₄
(c) MgCl₂
(d) CaCl₂

Buckminsterfullerene is an allotropic form of the element:
(a) phoshorus
(b) fluorine
(c) carbon
(d) sulphur

Out of KCl, HCl, CCl₄ and NaCl, the compounds which are not ionic are:
(a) KCl and HCl
(b) HCl and CCl₄
(c) CCl₄ and NaCl
(d) KCl and CCl₄

The number of covalent bonds in pentane (molecular formula C₅H₁₂) is:

One of the following compounds is not ionic in nature. This compound is:
(a) Lithium chloride
(b) Ammonium chloride
(c) Calcium chloride
(d) Carbon tetrachloride

A covalent molecule having a double bond between its atoms is:
(a) Hydrogen
(b) Oxygen
(c) water
(d) ammonia

The molecules having triple bond in them are:
(a) oxygen and ethyne
(b) carbon dioxide and ammonia
(c) methane and ethene
(d) nitrogen and ethyne

One of the following contains a double bond as well as single bonds. This is:
(a) CO₂
(b) O₂
(c) C₂H₄
(d) C₂H₂