244 Laboratory Manual for General, Organic, and Biological Chemistry
6. Classify each of the following compounds according to its functional group.
a. [tex]$CH _3- CH _2- CH = CH - CH _3$[/tex]
b. [tex]$CH _3- CH _2- CH _2- OH$[/tex]
c. [tex]$CH _3- CH _2- CH _2- O - CH _2- CH _3$[/tex]
d.
e.
Answer (2)
Compound a ( C H 3 − C H 2 − C H = C H − C H 3 ) contains a carbon-carbon double bond, thus it is an alkene.
Compound b ( C H 3 − C H 2 − C H 2 − O H ) contains an -OH group, thus it is an alcohol.
Compound c ( C H 3 − C H 2 − C H 2 − O − C H 2 − C H 3 ) contains a C-O-C linkage, thus it is an ether.
The functional groups are: a. Alkene, b. Alcohol, c. Ether. a. Alkene, b. Alcohol, c. Ether
Explanation
Understanding the Problem We are given three organic compounds and asked to identify their functional groups. Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules.
Identifying Functional Group in Compound a a. The compound C H 3 − C H 2 − C H = C H − C H 3 contains a carbon-carbon double bond (C=C). This indicates the presence of an alkene functional group.
Identifying Functional Group in Compound b b. The compound C H 3 − C H 2 − C H 2 − O H contains an -OH group bonded to a carbon atom. This indicates the presence of an alcohol functional group.
Identifying Functional Group in Compound c c. The compound C H 3 − C H 2 − C H 2 − O − C H 2 − C H 3 contains an oxygen atom bonded to two carbon atoms (C-O-C). This indicates the presence of an ether functional group.
Examples
Understanding functional groups is essential in organic chemistry as they dictate the chemical behavior of molecules. For example, the presence of an alcohol group (-OH) allows a compound to participate in hydrogen bonding, affecting its boiling point and solubility. Similarly, alkenes (C=C) are more reactive than alkanes due to the presence of the pi bond, making them useful in polymerization reactions to create plastics and other polymers. Ethers (C-O-C) are often used as solvents due to their ability to dissolve a wide range of organic compounds.
The classifications of the compounds are: a. Alkene, b. Alcohol, and c. Ether. Each compound's functional group is determined by the specific structures and bonds present within them. Understanding these functional groups is crucial in organic chemistry as they dictate the chemical behavior of the molecules.
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