13
Carbon: An Important Element
IMPORTANT POINTS:
Carbon (C) a non-metal with atomic number and atomic mass number 12 configuration is (24) and its valency is 4. Carton ablet abundantly in nature is free as well as combined form Carbon is an essential element in all organic compounds. Carbon shows the property of allotropy. It has crystalline as well as non-crystallineamorphous allotropes Diamond, graphite and fullerene are the crystalline allotropes where as coal, charcoal, coke ac are non-crystalline aftotropes > Diamond is the hardest of all the known natural substances. In diamond, each carbon atom bonded to four neighbouring carbon atoms thereby forming a tetragonal three-dimensiona structure ▸ Graphite has a hexagonal layered structure. Every carbon atom is bonded to three othe atoms ▸ Fullerene has a Bucky ball like structure. C C C C C the examples of Coal is of four types depending upon its carbon contents. Pat Lights, Buninou o and anthracite are types which have increasing percentage of carbon in them Charcoal is made by burning bones, wood etc. in insufficient supply of ow After taking out coal gas from coal, what remains is coke. ▸ Carbon has a property of catenation i.e. ability to form covalent bonds between carb atoms. That is why carbon can form innumerous compounds The compounds formed by carbon and hydrogen only are called hydrocarbons and are comma to be the basic compounds. Other carbon compounds are considered to be derived from hyde bons The hydrocarbons having only single bonds between carbon atom are called saturated hydroc bons. The hydrocarbons which have at least one double or triple bond between carbon ato called unsaturated hydrocarbons. Methane, ethane, propane etc are saturated hydrocarbon where as ethene, ethyne, propene, propyne etc. are called unsaturated hydrocarbons ▸ Carbon dioxide (CO) can be prepared in laboratory by the chemical reaction of dilute a calcium carbonate. It is of acidic nature and changes blue litmus red. If passed through time it turns lime water milky. ▸ In fire extinguishers, carbon dioxide is produced which is used as fire extinguisher ▸ Methane (CH) is the simplest saturated hydrocarbon.
SPECIMEN QUESTIONS ****
(1) is a good conductor of electricity.
(1) Coke
(2) Graphite
(3) Diamond
(4) Coal
Explanation: Graphite is the only form of carbon which is a good conductor of electricity.
Option 2 is correct.
(2) For glass cutting- -is used.
(1) diamond
(2) graphite
(3) fullerene
(4) lignite
Explanation: Diamond is the hardes substance, hence it is used to cut glass. .
.Option is correct.
3) is a saturated hydrocarbon.
(1) Ethene
(2) Ethyne
(3) Propene
(4) Butane
Explanation: Butane is a saturated hydrocarbon. .
.Option 4 is correct.
Which of the following is the form of coal having maximum percentage of carbon in it? (1) Peat
(2) Bituminous coal
(3) Anthracite
(4) Lignite
Explanation: Anthracite contains about 95% of carbon and is the form of coal having the highest percentage of carbon.
Option 3 is correct.
QUESTIONS FOR PRACTICE >>
(1) knives are used in eye surgery.
(1) Graphite
(2) Diamond
(3) Charcoal
(4) Fullerene
(2) Diamond
(2) In arc lamps giving bright light,- -is used. (1) graphite
(2) diamond
(3) charcoal
(4) fullerene
(1) graphite
(3) Valency of carbon is —
. (1) 1
(2) 2
(3) 3
(4) 4
(4) 4
(4) The pure coal that remains when coal gas is taken out from coal is called
(1) peat
(2) graphite
(3) diamond
(4) coke
(4) coke
(5) Solid is called as dry ice.
(1) methane
(2) coal
(3) carbon dioxide
(4) graphite
(3) carbon dioxide
(6) Boiling point of methane is—°C.
(1)-161.5
(2)-116.5
(3)-182.5
(4)-128.5
(1)-161.5
(7) - is also called as marsh gas.
(1) Ethane
(2) Methane
(3) Propane
(4) Butane
(2) Methane
(8) Which of the following chemicals is used in fire extinguisher?
(1) NaCl
(2) NaHCO,
(3) Na SO
(4)CaSO
(2) NaHCO,
(9) Liquified from coffee. is used to remove caffeine
(1) methane
(2) butane
(3) carbon dioxide
(4) nitrogen
(3) carbon dioxide
(10) The chemical formula for ethane is-
(1) CH
(2) CH
(3) CH
(4) C,H,
(1) CH
(11) Carbon dioxide is by nature.
(1) acidic
(2) basic
(3) neutral
(4) amphoteric
(1) acidic
(12) Which of the following hydrocarbons is an unsaturated hydrocarbon?
(1) CH
(2) CH (3) CH
(4) CH,
(4) CH,
(13) -is used as a lubricant.
(1) peat
(2) graphite (3) diamond (4) coke
(2) graphite
(14) --is used as a catalyst in water purification. (1) peat (2) graphite (3) diamond (4) fullerene
(4) fullerene
(15) The electronic configuration of carbon is (1) (2,2) (2) (2,3) (3) (2, 4) (4) (2,6)
(3) (2, 4)
(16) - - is the main component of biogas. (1) Methane (2) Carbon dioxide (3) Carbon monoxide (4) Butane
(1) Methane
(17) Which of the following is an amorphous form of carbon? (1) Coke (2) Diamond (3) Fullerene (4) Graphite
(1) Coke
(18) The percentage of carbon dioxide present in atmosphere is—. (1)21% (2) 78% (3) Less than 1% (4) more than 3%
(3) Less than 1%
(19) Structure of is tetragonal three dimensional. (1) Coke (2) Diamond (3) Fullerene (4) Graphite
(2) Diamond
(20) - is used for making electrodes. (1) Coke (2) Diamond (3) Fullerene (4) Graphite
(4) Graphite
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