In this article, we will learn about substitution reactions of alkanes. We will discuss the substitution reactions of alkanes through examples.
What are alkanes?
Alkanes are saturated hydrocarbons. There are single
covalent bonds between carbon atoms.
What is substitution reaction?
The substitution reaction is a reaction in which one
atom or group of atoms is replaced by other atoms or atoms.
What is substitution reaction of alkanes?
Alkanes are inert in the presence of most of the reagents
but chlorine in the presence of sunlight replaces hydrogen atoms of alkanes one
by one. This is how substitution reaction takes place in alkanes.
Substitution reaction of alkanes examples
Methane does not react with chlorine in the dark but in
the presence of sunlight, all hydrogen atoms are replaced by chlorine one by
one.
Following are the reactions of substitution reactions
of methane
Methane reacts with chlorine to produce chloromethane (Methyl
chloride) in the presence of sunlight.
CH4 +Cl2 →CH3Cl + HCl
Chloromethane reacts with chlorine to produce dichloromethane
CH3Cl +Cl2 →CH2Cl2 +
HCl
Dichloromethane reacts with chlorine to produce
trichloromethane or chloroform.
CH2Cl2 + Cl2 →CHCl3
+ HCl
Chloroform reacts with chlorine to produce carbon tetrachloride.
CHCl3 + Cl2 →CCl4 +
HCl
So we can easily understand through the reaction of
methane with chlorine that all the hydrogen atoms are replaced by chlorine.
Related Topics
FAQs
1. Why
do alkanes only undergo substitution reactions?
Ans – Alkanes are saturated hydrocarbons with single covalent
bonds between carbon atoms and these bonds are strong bonds.
In alkanes, carbon has no free valence electron to
share with other atoms so alkanes do not undergo an addition reaction.
That’s why they only undergo substitution reactions.
2. Why
are substitution reactions of alkanes not very practical?
Ans – Alkanes are relatively unreactive. They require
specific conditions like heating or sunlight. That’s why substitution reactions
of alkanes are not very practical.
3. What is the condition of the substitution reaction of methane with chlorine?
Ans- The substitution reaction of methane with chlorine
occurs in the presence of sunlight or ultraviolet light.
4. Why
is the reaction between methane and chlorine considered a substitution reaction?
Ans- Because in this reaction, all hydrogen atoms are
replaced by chlorine atoms one by one in the presence of sunlight.
substitution reaction of alkanes with halogens
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