Amorphous forms of carbon| How prepare | Classification

AMORPHOUS form of CARBON

     The word amorphous means lacking in form or shape. Thus, amorphous forms of carbon such as charcoal, coke and lamp black have no particular shape of structure. Their atoms of molecules or not arranged in any regular geometrical pattern. 

COAL

  Occurence :- It is one of the cheapest fossil fuels which is formed in nature as result of slow decomposition of decayed vegetable matter under the influence of heat and pressure where supply of air is limited. This process is known as  𝘾𝙖𝙧𝙗𝙤𝙣𝙞𝙯𝙖𝙩𝙞𝙤𝙣 and most of this activity occured in the Carboniferous era  about 270  million  years ago.  Carbonization of vagetable matter over millions of years resulted in the formation of four varities of coal, which vary with respect to their carbon content. The four varities are  𝙥𝙚𝙖𝙩, 𝙡𝙞𝙜𝙣𝙞𝙩𝙚, 𝙗𝙞𝙩𝙪𝙢𝙞𝙣𝙤𝙪𝙨, & 𝙖𝙣𝙩𝙝𝙧𝙖𝙘𝙞𝙩𝙚. 

Peat :- It is the first stage in the formation of coal. So it is the most inferior form of coal.  It contains 50-60% carbon. 

Lignite :- It is the second stage in the formation of coal and is harder than peat. It contains more than 60-70% carbon. 

Bituminous :- It is the third stage in the formation of coal. It is the most common variety of coal and is also known as household coal. It contains 80-90% carbon.  

Anthracite :- It is the last stage in the formation of coal and is the purest variety of  coal. It is hard and difficult to ignite, but once ignited it burns with a lot of heat and for a very long time. It contains 90-98% carbon. 

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Uses of Coal

   1:- As fuel in houses, thermal power stations, steam engines and furnaces. 

   2:-  In the preparation of coke, coal gas and coal tar. 

   3:- In the manufacture of synthetic petrol. 

   4:- In the manufacture of some drugs, fertilizers, synthetic, textiles and perfumes. 

   5:-  As a source of organic compounds such as benzene, naphthalene, aniline, etc. 

COKE

    Many products like coke, coal tar, ammonia are produced when coal is subjected to destructive distillation. When high temperature is attained during the process of destructive distillation of coal, them volatile products are given of and residue left behind is coke. It is pure form of carbon. A wide range of by products, e.g. coal gas, coal tar, ammonia are obtained. 

Uses of Coke

   1:- Coke is used extensively as a fuel because it burns without smoke. 

  2:- Used as a reducing agent for the extraction metals from their oxides and sulphide ores.

 3:- Being a good conductor of electricity it is used in the lining of furnaces and in making electrodes. 

Coal tar :- It is a foul smelling, dark broun liquid. In fractional distillation it yields many organic compounds such as benzene, toluene, etc. There are used for making dyes, drugs and explosives. 

Coal gas :- It is a mixture of methane, carbon monoxide, and other gases. Purified coal gas is used as an industrial household fuel. 

CHARCOAL

      When a solid organic substances is subjected to destructive distillation, that is heated strongly in the absence of air, then, a grey and porous solid is obtained, which is called charcoal.         

  Depending upon the source used, charcoal is categorised into three types

      1:- Wood charcoal

      2:- Bone charcoal

      3:- Sugar charcol

 1:- Wood charcoal:- wood, when subjected to strong heat in the absence of air gets burnt to charcoal, leaving behind volatile impurities. 

  Properties of wood charcoal. 

     1:- wood charcoal is black, porous, soft and brittle solid. 

    2:- though it is heavier than water (Sp.gr=1.5) yet due to it's high porosity and the air contained in the pores floats on water. If air is removed from the pores by boiling the wood charcoal then it would gradually set down. 

    3:- It is a good  𝙖𝙙𝙨𝙤𝙧𝙗𝙚𝙣𝙩* of gases, liquid and solids. 

    4:- When it is heated in air or oxygen to 100°C, it burns without a flame to form carbon dioxide gas.

Uses of wood charcoal. 

    1:- As a fuel because it burns at low temperature and produces no smoke

    2:-As a reducing agent in the extraction of metals from their respective oxides. 

    3:- It is a constituent of gun powder used  as an explosives in guns and rifles. 

   4:- due to it's high adsorbing capacity, wood charcoal is used. 

 • to adsorb harmful gases in military and industrial gas masks. 

 • in the form of tablets by persons suffering from indigestion and gastric problems, the tablets relieve has pressure by adsorbing stomach gases. 

 • in making filters  and sieves. 

2:- Sugar Charcoal :- It is obtained by heating cane-sugar or glucose in the absence of air and is the purest form of amorphous carbon. Sugar charcoal is also prepared by the dehydration of cane- sugar or glucose in the presence of concentrated H2SO4. The acids absorbs water, leaving behind carbon. 

    Uses of Sugar charcoal.  

   1:- Being a pure form of carbon, it is used as a reducing agent to obtain metals from their oxides. 

   2:- Used to Decolourise coloured solutions. 

3:- Bone Charcoal :- when animal bones are subjected to destruction distillation, then bone charcoal is produced along with bone oil and pyridine. Bone charcoal contains mainly calcium phosphate (to the extent of 80%) and about 10-12% of amorphous carbon. Because of this composition, bone charcoal possesses the remarkable property of adsorbing colouring matter from liquids. 

  Uses of bone charcoal

     1:- to remove flouride from water

    2:- to filter aquarium water

    3:- to refine crude oil in the production of vaseline

   4:- As a Decolourizing agent in sugar refining industry. Bone charcoal removes the brown colour from sugar syrup before crystallising. 

   5:- the carbon content of bone charcoal is separated by treating the latter with the hydrochloric acid, which dissolves the calcium phosphate. Carbon is then Filtered out of the solution. This carbon is ivory black and is used as a black pigment in artistic painting because it is the deepest available black. 

GAS CARBON 

     When coal is destructively distilled, gas carbon is deposited on the sides and roofs of retort in which this process is carried out. It is a very pure form of carbon. It is grey in colour and is a good conductor of heat and electricity. It is used for making the electrodes of dry cells. 

LAMP BLACK (SOOT)/ CARBON BLACK

   It is prepared by heating carbon- rich substances like turpentile oil or kerosene in a limited supply of air. The black smoke is deposited in the form of fine Black powder on cold surfaces of the combustion chamber. This fine powder is 𝙡𝙖𝙢𝙥 𝙗𝙡𝙖𝙘𝙠 𝙤𝙧 𝙨𝙤𝙤𝙩 which in our homes is called 𝙠𝙖𝙟𝙖𝙡 𝙤𝙧 𝙨𝙪𝙧𝙢𝙖. All kinds of smoky flames are sources of lamp Black 

Uses of Lamp Black

   1:- In making black  shoe polish, carbon paper, printing ink, Black paint, etc. 

  2:- In the hardening of rubber tyres. 

  3:- As kajal. 

    

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