The understandable notes- Carbon and its compounds, Class 10, Part-2
ALLOTROPES OF CARBON
Allotropes are different structural arrangement of same element. Since allotropes consist of same atom their chemical properties remains same but the difference lies in their physical properties. Allotropes have different arrangements of atom inside them. Carbon also possess the property of forming allotropes.
( Allotropes kisi bhi element ke judwa bhai behan hote hai. Allotropes ke andar atom alag alag tarah se arranged hote hai. Yani ki same element ke atoms different tarah se ek dusre se bond banate hai. Ab is se chemical properties pr to koi asar nhi padta lekin physical properties kafi change ho jati hai. Aur carbon kai bhi kai allotropes exist krte hai jinhe hum abhi padhenge. Aur inhe dhyan se padh lena kyonki inse kai question tarah ke questions bante hai.)
DIAMOND
Diamond is an allotrope of carbon in which one atom is bonded to four other atoms forming a rigid three dimensional structure. Diamond is used as jewellery and is the hardest natural occurring substance. Diamond has a shiny surface. The structure of diamond is given below
In the diagram you can see that one atom is bonded to four other carbon atoms forming a three dimensional structure. Diamond can also be synthesized bu subjecting carbon to very high pressure. These are small in size but indis
( Heera, iske bare mai to sabko pata hi hoga ki hardest natural occurring substance hai. Natural occuring ka matlab jo nature se mila ho. Ab diamond bhi carbon ka hi ek allotrope hai. Ye to suna hi hoga ki coal ki khan mai hi hira milta hai, to isi liye milta hai ki dono same atom se bane hote hai. Ab diamond mai carbon ka ek atom 4 aur atom se bonded rehte hai to ek 3 dimensional hard structure taiyar hota hai. Baki diamond ka use to sabko pata hi hoga. Uske alawa dimond ko glass cutter mai bhi use krte hai. Aur kya kuch nhi bas itna sufficient hai.)
GRAPHITE
Graphite is another allotrope of carbon in which one carbon atom is bonded to three other carbon atom. One of the bond is double bond and thus the valency of carbon is satisfied. Graphite is smooth and slippery in nature. Graphite is also a good conductor of electricity because one electron is free to roam. Graphite is used a lead of pencil. each carbon atom is bonded to three other carbon atoms in the same plane giving a hexagonal array. The structure of graphite is given below.
In the diagram you can see that one atom is bonded to three other carbon atom.
( Ab diamond ki hi tarah graphite bhi carbon ka ek allotrope hai. Bas fark itna hai ki ek carbon atom teen aur carbon atom se same plane mai bonded hai. Matlab graphite ka structure 2 dimensional hai. Jabki diamond ka three dimensional hota hai. To graphite mai free electron hone ki wajah se electricity ka good conductor hota hai. Agar nature ki baat kre to ye smooth aur slippery hota hai aur pencil ki lead mai iska use hota hai. Ab ye dekho ki pencil ki lead kitni brittle hoti hai yani ki thoda sa extra force lagane se hi tut jata hai aur diamond kitna hard hota hai. Bas allotropes mai ye do hi important hai baki ek aur hai vo itna kaam ka nhi hai.)
Fullerenes form another class of carbon allotropes. The first one to be identified was
C-60 which has carbon atoms arranged in the shape of a football. Since this looked
like the geodesic dome designed by the US architect Buckminster Fuller, the molecule
was named fullerene.
( Baki fullerene bhi carbon ka hi ek allotrope hota hai jisme carbon ke 60 atoms hote hai. Is 60 wale ko C-60 bolte hai. Aise hi 70 wale ko C-70 or 80 wale ko C-80. Or inka structure kuch kuch football jaisa hota hai.)
VERSATILE NATURE OF CARBON
The number of compound containing carbon is estimated in millions. Why carbon have so large number of compounds. Carbon possess some unique properties due to which it can form a large number of compound. The are primarily two properties of carbon.
( Ab carbon se bane hue compounds ki value crores mai hai. Baki kisi element ki to chodo ek taraf carbon containing compound rakh do aur dusri taraf vo sare compounds jinme bas carbon nhi hai baki sab hai to bhi carbon compounds ka number unse bahut jyada rahega. Ab carbon ke paas kuch to unique hoga hi kiski wajah se vo itne sare compounds bana pa raha hai. To carbon ke paas aisi 2 properties hai jinhe hum niche padhenge.)
Carbon has the unique ability to form bonds with other atoms of carbon, giving rise to large molecules. This property is called catenation. These compounds may have long chains of carbon, branched chains of carbon or even carbon atoms arranged in rings. In addition, carbon atoms may be linked by single, double or triple bonds. Compounds of carbon, which are linked by only single bonds between the carbon atoms are called saturated compounds. Compounds of carbon having double or triple bonds between their carbon atoms are called unsaturated compounds.
( Dekho carbon catenation ki unique property to exhibit krta hai. Matlab ki ek carbon atom dusre carbon atoms se bond bana sakta hai. Bond kitne bhi atoms ko contain kr sakta hai. Aur no of atoms se properties pr bhi asar padta hai. Ab ye socho ki jab carbon ka ek atom hai to uske kitne compounds honge fir 2 fir 3 aur aise hi kitne sare compounds ban jayenge. Iske baad jo bonds banenge vo straight bhi ho sakte hai, branched bhi aur ring like structure bhi. Jinhe in terms mai confusion hai vo nomenclature tak ka weight kr lo. Iske baad ye single bonded bhi ho sakte hai, double bonded bhi aur triple bonded bhi, aur har bond ki property bhi alag hoti hai. Just imagine 5 carbon straight bonded hai to vo alag hai ring se bonded hai to vo alag hai, branched hai to vo alag hai, single double ya triple bonded hai to vo alag hai, aur ring mai single,double,triple bonded hai to vo alag hai matlab kitne sare compounds to aise hi ban jayenge. Aur ek baat agar pure compound mai ek bhi double bond hai to vo double bond wali category mai aa jayega fark nhi padta ki chahe for kitne single bond ho aur agar ek triple bond ho to fark nhi padega ki kitne double ya single bond hai. Ab jin compoundsmai sirf single bond honge vo saturated compounds ki category mai aaenge aur jine double ya triple bond honge vo unsaturated compounds honge.)
No other element exhibits the property of catenation to the extent seen in carbon compounds. Silicon forms compounds with hydrogen which have chains of upto seven or eight atoms, but these compounds are very reactive. The carbon-carbon bond is very strong and hence stable. This gives us the large number of compound with many carbon atoms linked to each other.
( Carbon ke alawa koi bhi element catenation ki property ko show nhi krta. Par chemistry mai har chiz ka exception hai. To silicon kuch 6-7 atom tak catenation ki property k show krta to hai pr ye compoumds kafi jyada reactive ho jate hai. Carbon Carbon ka bond kafi strong aur stable hota hai. To isi wajah se carbon kai bonds bana pata hai.)
TETRAVALENCY-
Carbon is capable of forming bonds with four other atoms of carbon or some monovalent atoms because its valency is four. Carbon forms compounds with hydrogen, oxygen, nitrogen, sulphur etc. The properties of these compounds depends on the atom other than carbon present in the compounds.
( Dekho carbon ki valency four hoti hai yani ki ek carbon atom 4 aur carbon atom ke sath bond banane ki capability rakhta hai ya fir 4 monovalent atom ki jinki valency 1 ho. Carbon hydrogen, oxygen, nitrogen, sulphur, chlorine wagera ke sath bonds banata hai. Aur in compounds ki properties carbon kai alawa jo atom present hai un par depend krti hai.)
The bonds that carbon forms with most other elements are very strong making these compounds exceptionally stable. One reason for the formation of strong bonds by carbon is its small size. This enables the nucleus to hold on to the shared pairs of electrons strongly. The bonds formed by elements having bigger atoms are much weaker.
( Ab jo bond carbon aur elements ke sath banata hai vo bhi kafi strong hote hai jisse ye compounds kafi jyada stable ho jate hai.Ba strong bond ban ne ka ek karan ye bhi hai ki carbon ke atom ka size small hota hai. Ab size small hone se jo nucleus ka asar electrons par jyada hoga aur vo electons ko tightly hold krke rakhegi. Ab jin atoms ka size small hoga vo carbon ke sath strong bonding krenge un atoms ke comparison mai jinka size bada hoga. To dekho carbon ki in do properties se hi carbon exceptionally kafi jyada compounds bana pata hai.)
SATURATED AND UNSATURATED COMPOUNDS
The compounds having only single bond is called saturated compounds.
Now look at ethane which contains two carbon atoms.
These compound have maximum number of hydrogen. Saturated compounds are generally non reactive as compared to unsaturated compounds. When subject to combustion, these compounds gives a clean flame and release carbon dioxide. Saturated compounds are also used widely as a fuel because of following reasons-:
- They contain a lot of energy stored in their bond so when they burn in the presence of oxygen they release a lot of heat.
- Saturated compounds burns more cleanly and with a smokeless flame because the primary products formed during combustion is Carbon dioxide and water.
- They are more efficient and less polluting as compared to unsaturated compounds.
- They are less reactive in nature so they are easy to carry and transport.
- They are readily available in the environment and thus used widely as a fuel.
Unsaturated compounds are those compounds which contain double bond or triple bond. The compounds containing double bond are called alkenes and the compounds containing triple bond is called alkynes.
Look at ethene, in ethene carbon carbon bond is double and other bonds with hydrogen are single. Look at the structure of ethene
( Ab jin carbon compounds mai double ya triple bond hote hai unhe unsaturated compounds bolte hai. Ab jaise ethene hai to usme carbon cerbon kai beech mai double bond hai. Double bond wale compounds ko alkenes bolte hai aur triple bonds wale ko alkynes.)
This is the electron dot structure of ethene. Similarly the structure of ethyne is given below
And the electron dot structure of ethyne is given below
(To ye to samajh aa gaya hoga ki jis compound mai double ya triple bond hota hai unhe unsaturated compounds kehte hai. Baki ethene aur ethyne ka structure bhi bana diya. Abhi ene aur yne ke bare mai itna nhi pata hoga lekin nomenclature ke baad sab samajh aa jayega..)
Unsaturated carbon compounds are used in making of plastic and ethyne or acetylene is used for welding. Ethyne is used for welding because when it burns in the presence of oxygen it reaches a very high temperature.
( Unsatutated compounds ko plastic manufacturing mai use krte hai. Aur iske sath ethyne gas ko welding mai bhi use krte hai. Ye mcq aaya tha mujhe. Ethyne gas jise acetylene bhi kehte hai vo jalte time itne high temperature par pahuch jati hai ki iron ya steel ko weld kr sake. Iske sath ethyne jalti bhi bikkul clean flame ke sath hai. To is part mai itna hi baki ka agle part mai padhenge. )
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