Question

Give reasons for the following:
(a) Elements carbon forms compounds mainly by covalent bonds.
(b) Diamond has a high melting point.
(c) Graphite is a good conductor of electricity.
(d) Acetylene burns with a sooty flame.
(e) Kerosene does not decolourised bromine water while cooking oils do.

Answer 1

a) elements of carbon forms compounds mainly by covalent bonds because it has 4 electrons in its outermost shell and can be the gain electrons not give electrons so it forms covalent bonds by sharing of electrons.
b) Diamond has a high melting point because the forces of attraction between the molecules of diamond is very large and a large amount of heat is in the form of energy of heat is required to break that bonds between the Diamond molecules.
c) graphite is a good conductor of electricity because it contains free molecules which contains electrons which helps in conduction of electricity.
d) acetylene burns with a sooty flame because it contains a high percentage of carbon in it which when react with oxygen gets oxidized carbon dioxide and give soot.
e) kerosene does not colour Rises bromine water while cooking oils does because cooking oil contains unsaturated hydrocarbons that when react with bromine water forms in etyleline Bromide or 1122 tetrabromoethane

Answer 2

Explanation:

(i) It is because carbon has four valence electrons, it cannot gain or lose four electrons because high energy is needed. It can only share four electrons.

(ii) It is due to strong covalent bonds and compact structure of diamond.

(iii) It is due to presence of free electrons in graphite because each carbon is linked to three more carbon atoms.

(iv) It is due to high percentage of carbon, it burns with sooty or smoky flame.

(v) Kerosene oil is mixture of saturated hydrocarbons therefore does not decolourise bromine water.

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