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226 Chemistry: Matter and Change
Solving Problems: A Chemistry Handbook
SOLVING PROBLEMS:
A CHEMISTRY HANDBOOK
CHAPTER 22
bromine atoms, the prefix for bromine becomes tribromo-. The fluorine atom is on carbon 2. That number is indicated before the prefix
fluoro-. The name of the compound is 1,1,2-tribromo-2-fluoropropane.
Practice Problems
1. Name the following halocarbons.
Substitution reactions A substitution reaction is one in which
an atom or a group of atoms in a molecule is replaced by another
atom or group of atoms. If hydrogen atoms in alkanes are replaced
by halogen atoms, the substitution process is called halogenation. In
turn, the halogen atoms in alkyl halides can be replaced by another
atom or group of atoms by means of another substitution reaction.
Example Problem 22-2
Writing Equations for Substitution Reactions
Write a balanced chemical equation for the substitution reaction in
which one of the hydrogens on an end carbon of butane is replaced
by a chlorine atom through reaction with elemental chlorine. Name
the resulting compound.
Butane is a four-carbon alkane and thus has the formula C 4 H 10 ,
which can be represented as CH 3 CH 2 CH 2 CH 3 .
Elemental chlorine has the formula Cl 2 . Thus, the reactant side of
the equation is CH 3 CH 2 CH 2 CH 3 ϩ Cl 2 .
One of the two chlorine atoms replaces one hydrogen atom on an
end carbon. The other chlorine atom combines with the displaced
hydrogen atom, forming hydrogen chloride, a product. The alkyl
halide formed has one chlorine atom, which is located on carbon 1.
The complete equation is CH 3 CH 2 CH 2 CH 3 ϩ Cl 2 0
CH 3 CH 2 CH 2 CH 2 Cl ϩ HCl and is balanced as written.
The halocarbon formed is 1-chlorobutane.
▲
H C
Cl
Cl
C C
H
Br
H
H
F
F
Cl
a.
b.