Give reason for the following -
1) element carbon forms compounds mainly by covalent bonding.
2) diamond has a high melting point.
3) graphite is a good conductor of electricity.
4) acetylene burns with sooty flame .
5) kerosene does not de colourise bromine water while cooking oils do.
Answers
ANSWERS
1) Carbon forms compounds mainly by covalent bonding because in its outermost shell carbon has four electrons and needs to gain or loss 4 electrons to attain noble gas configuration and it can't loose or gain electrons as it takes more energy than the nucleus could , so it shares electrons to form compounds by covalent bonding.
2) In the structure of diamond each carbon atoms are bonded to four other carbon atoms so the bonding is very strong and it takes a huge amount of energy to separate these carbon atoms , so as a result diamond has a high melting point.
3) In the structure of carbon each carbon atoms are bonded with three other carbon atoms , while one of them remains de-localized and is free due to this graphite is a good conductor of electricity.
4) Acetylene burns with sooty flame as it is an unsaturated hydrocarbon it has more percentage of carbon than hydrogen and hence will not undergo complete combustion resulting in a sooty flame .
5) Kerosene does not decolourise bromine water while cooking oils do because cooking oils are unsaturated hydrocarbons while kerosene is a saturated hydrocarbon and decolourisation of bromine water can only be done by unsaturated hydrocarbons by undergoing addition reaction.