English Medium इयत्ता १० - CBSE Question Bank Solutions for Science

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

Which of the following has a triple bond as well as single bonds?
(a) ethene
(b) methane
(c) ethyne
(d) nitrogen

The organic compound prepared by Wohler from an inorganic compound called ammonium cyanate was:
(a) glucose
(b) urea
(c) uric acid
(d) vinegar

One of the following is not an allotrope of carbon. This is:
(a) diamond
(b) graphite
(c) cumene
(d) buckministerfullerene

Two non-metals combine with each other by the sharing of electrons to form a compound X.
(a) What type of chemical bond is present in X?
(b) State whether X will have a high melting point or low melting point.
(c) Will it be a good conductor of electricity or not?
(d) Will it dissolve in an organic solvent or not?

A saturated hydrocarbon has fifty hydrogen atom in its molecule. The number of carbon atoms in its molecule will be
(a) twenty five
(b) twenty four
(c) twenty six
(d) twenty seven

A hydrocarbon having one double bond has 100 carbon atoms in its molecule. The number of hydrogen atoms in its molecule will be
(a) 200
(b) 198
(c) 202
(d) 196