English Medium Class 10 - CBSE Question Bank Solutions for Science

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

The electronic configurations of three elements X, Y and Z are as follows:

(a) Which two elements will combine to form an ionic compound?
(b) Which two elements will react to form a covalent compound?
Give reasons for your choice.

Which of the following cannot exhibit isomerism?
(a) C₄H₁₀
(b) C₅H₁₂
(c) C₃H₈
(d) C₆H₁₄

The pencil leads are made of mainly:
(a) lithium
(b) charcoal
(c) lead
(d) graphite

The number of isomers formed by the hydrocarbon with molecular formula C₅H₁₂ is:
(a) 2
(b) 5
(c) 3
(d) 4

An element A has 4 valence electrons in its atom whereas element B has only one valence electron in its atom. The compound formed by A and B does not conduct electricity. What is the nature of chemical bond in the compound formed? Give its electron-dot structure.

The number of carbon atoms joined in a spherical molecule of buckminsterfullerene is:
(a) fifty
(b) sixty
(c) seventy
(d) ninety

A solid element X has four electrons in the outermost shell of its atom. An allotrope Y of this element is used as a dry lubricant in machinery and also in making pencil leads.
(a) What is element X?
(b) Name the allotrope Y.
(c) State whether allotrope Y is a good conductor or non-conductor of electricity.
(d) Name one use of allotrope Y (other than lubrication and pencil leads)
(e) Name two other allotropes of element X.

The electronic configurations of two elements A and B are given below:

(a) What type of chemical bond is formed between the two atoms of A?
(b) What type of chemical bond will be formed between the atoms of A and B?

You can buy solid air-freshners in shops. Do you think these substance are ionic or covalent? Why?

Give the formulae of the chlorides of the elements X and Y having atomic numbers of 3 and 6 respectively. Will the properties of the two chlorides be similar or different? Explain your answer.

An element E exists in three allotropic forms A, B and C. In allotrope A, the atoms of element E are joined to form spherical molecules. In allotrope B, each atom of element E is surrounded by three other E atoms to form a sheet like structure. In allotrope C, each atom of element E is surrounded by four other E atoms to form a rigid structure.
(a) Name the element E.
(b) What is allotrope A.
(c) What is allotrope B?
(d) What is allotrope C?
(e) Which allotrope is used in making jewellery?
(f) Which allotrope is used in making anode of a dry cell?

What happens when methane (natural gas) burns in air? Write the chemical equation of the reaction involved.

Write the balanced equation for the following chemical reaction.

\[\ce{Barium chloride + Aluminium sulphate -> Barium sulphate + Aluminium chloride}\]