Saturated Hydro carbons are chemically least reactive and undergo substitution reaction". Explain with examples.
Answers
Answer:
Hydrocarbons are sub-divided into two main groups, the aliphatics(open) & cyclic(closed) chain compounds. The open chain compounds or aliphatic compounds are furthur sub-divided into saturated compounds & unsaturated compounds.
Under the saturated hydrocarbons all the four valencies of each carbon atom are satisfied by forming single covalent bonds with carbon & with hydrogen atoms.
Carbon atoms here are joined only by a single covalent bond. They are represented by the formula CnH2n+2
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----C-----C----
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They are less reactive due to the non availability of electrons in the single covalent bond, & therefore undergo substitution reaction.
Substitution reaction: A chemical reaction in which one atom of a molecule is replaced by another atom (or group of atoms)is called a substitution reaction.
Eg: CH4 + Cl2 ----> CH3Cl + HCl
Other examples:
- Methane
- Ethane
- Propane
- Normal Butane
- Iso-butane or 2-methyl propane
Answer:saturated hydrocarbons are least reactive and undergoes substitution reaction.
Explanation:
Saturated hydrocarbons are those where no double bond is present in carbon chains.
carbon has 4 electrons in its outermost shell.
H
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H - C - H
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H
as in methane the 4 electrons of carbon is shared with 4 electrons of hydrogen one from each. So its outermost shell is completed with 8 electrons. They they are chemically least reactive. As they are stable with their complete outermost shell.
But in presence of sunlight or other catalyst that supports the reaction to be occured they show substitution reaction as in case of halogens.
halogens have 7 electrons in their outermost shell and has a high tendency to complete their octet. So they remove or replace the hydrogens from hydrocarbons and from bond with carbons sharing one electron.for example-
methane + bromine → methylbromine + hydrogen bromide
CH4 + Br2 → CH3Br + HBr