Carboxylic Acids Worksheet

Explanations


Blank Worksheet

Answers


 

1) butyric acid or butanoic acid
  1. The longest carbon chain of 4 is circled.
  2. But- is root for 4; -oic acid is the ending for a carboxylic acid.  The base name is butanoic acid.
  1. The chain is then numbered to give the carboxylic acid carbon the number 1.
  2. The final name is
    IUPAC name:  butanoic acid
    common name:  butyric acid

 

2) acetic acid or ethanoic acid
  1. The longest carbon chain of 2 is circled.
  2. Eth- is root for 2; -oic acid is the ending for a carboxylic acid. The base name is ethanoic acid.
  1. The chain is then numbered to give the carboxylic acid carbon the number 1.
  2. The final name is
    IUPAC name:  ethanoic acid
    common name:  acetic acid

 

3) 3-methylhexanoic acid
  1. The longest carbon chain of 6 is circled.
  2. Hex- is root for 6; -oic acid is the ending for a carboxylic acid.  The base name is hexanoic acid.
  1. The chain is then numbered to give the carboxylic acid carbon the number 1.
  2. There is a methyl group located at carbon 3.
  3. The final name is 3-methylhexanoic acid.

 

4) 6-chloro-4-ethyl-2-methyloctanoic acid
  1. The longest carbon chain of 8 is circled.
  2. Oct- is root for 8; -oic acid is the ending for a carboxylic acid.  The base name is octanoic acid
  1. The chain is then numbered to give the carboxylic acid carbon the number 1.
  2. There is a methyl group located at carbon 2, an ethyl group located at carbon 4, and a chloro group located at carbon 6.
  3. The final name is 6-chloro-4-ethyl-2-methyloctanoic acid

 

5) cyclohexanecarboxylic acid
  1. The longest chain of 6 is circled.  The carboxylic acid carbon is not included since it is not part of the ring.
  2. Hex- is root for 6.  Base name for the ring is cyclohexane
  1. The ring is numbered to give the carboxylic acid group the lowest number 1.
  2. the final name is cyclohexanecarboxylic acid.

 

6) 5-hydroxy-2,4-dimethylheptanoic acid
  1. The longest carbon chain of 7 is circled.
  2. Hept- is root for 7; -oic acid is the ending for a carboxylic acid.  The base name is heptanoic acid.   
  1. The chain is then numbered to give the carboxylic acid carbon the number 1.
  2. There is a methyl group located at carbons 2 and 4, an hydroxy group located at carbon 5.
  3. The final name is 5-hydroxy-2,4-dimethylheptanoic acid.

 

7) 3-bromo-2-propyl-5-methylhexanoic acid
  1. The longest carbon chain, including the carboxlic acid carbon, of 6 is circled.
  2. Hex- is root for 6; -oic acid is the ending for a carboxylic acid.  The base name is hexanoic acid.     
  1. The chain is then numbered to give the carboxylic acid carbon the number 1.
  2. There is a propyl group located at carbon 2, a bromo group located at carbon 3, and a methyl group located at carbon 5.
  3. The final name is  3-bromo-2-propyl-5-methylhexanoic acid

 

8) 4-chloro-2-methyl-3-butynoic acid or 4-chloro-2-methylbut-3-ynoic acid
  1. The longest carbon chain of 4 is circled.
  2. But- is root for 4; -yne is the suffix for an alkyne (triple bond) and -oic acid is the ending for a carboxylic acid.  The base name is butynoic acid.
  1. The chain is then numbered to give the carboxylic acid carbon the number 1.
  2. There is a methyl group located at carbon 2, and a chloro group at carbon 4.  The alkyne is located at carbon 3.
  3. The final name is
    traditional name:  4-chloro-2-methyl-3-butynoic acid
    or new form:  4-chloro-2-methylbut-3-ynoic acid.

 

9) (Z)-2-ethyl-4-methyl-3-isopropyl-3-octenoic acid or (Z)-2-ethyl-4-methyl-3-isopropyloct-3-enoic acid
  1. The longest carbon chain of 8 is circled.
  2. Oct- is root for 8; -ene is the suffix for an alkene (double bond) and -oic acid is the ending for a carboxylic acid.  The base name is octenoic acid
  1. The chain is then numbered to give the carboxylic acid carbon the number 1.
  2. There is an ethyl group located at carbon 2, an isopropyl group at carbon 3, and a methyl group located at carbon 4.  The alkene is located at carbon 3
  1. To tell which isomer we have the E/Z designation must be used.
  2. Now to determine priorities:  For the left side of the double bond, since both atoms are carbons (Z=6) we must go to the next adjacent atoms (highlighted in red in the next sentence).  The CH3 (1+1+1=3) takes the lower priority than CH2CH2CH2CH3 (1+1+6=8).  For the right side of the double bond, we once again have two carbons (Z=6) and must go to the next adjacent atoms (highlighted in red in the next sentence).  However, CH(CH3)2 (1+6+6=13) and CH(CH2CH3)(COOH) (1+6+6=13) still do not distinguish, so we must move to the next adjacent atoms (highlighted in blue in the next sentence).   Now we have CH(CH3)2 ((1+1+1)2=6) taking the lower priority to CH(CH2CH3)(COOH) (1+1+6+8+8+1=25).
  3. The groups with the higher priority are shown in red in the image.  Since they are on the same side of the double bond, this is the Z form.
  4. The final name is
    traditional name:  (Z)-2-ethyl-4-methyl-3-isopropyl-3-octenoic acid
    or new form: (Z)-2-ethyl-4-methyl-3-isopropyloct-3-enoic acid.

 

10) (Z)-4-ethoxy-5-iodo-3-methyl-3-nonenoic acid or (Z)-4-ethoxy-5-iodo-3-methylnon-3-enoic acid
  1. The longest carbon chain of 9 is circled.
  2. Non- is root for 9; -ene is the suffix for an alkene (double bond) and -oic acid is the ending for a carboxylic acid.  The base name is nonenoic acid
  1. The chain is then numbered to give the carboxylic acid carbon the number 1.
  2. There is a methyl group located at carbon 3, an ethoxy group at carbon 4, and a iodo group located at carbon 5.  The alkene is located at carbon 3.  
  1. To tell which isomer we have the E/Z designation must be used.
  2. Now to determine priorities:  For the left side of the double bond,  OCH2CH3 (Z=8) takes higher priority than CHICH2CH2CH2CH3 (Z=6). For the right side of the double bond, since both atoms are carbons (Z=6) we must go to the next adjacent atoms (highlighted in red in the next sentence).  The CH3 (1+1+1=3) takes the lower priority than  CH2COOH (1+1+6=8).
  3. The groups with the higher priority are shown in red in the image.  Since they are on the same side of the double bond, this is the Z form.
  4. The final name is
    traditional name:  (Z)-4-ethoxy-5-iodo-3-methyl-3-nonenoic acid
    or new form: (Z)-4-ethoxy-5-iodo-3-methylnon-3-enoic acid.

 

11) 2-butenoic acid or but-2-enoic acid
  1. The longest carbon chain of 4 is circled.
  2. But- is root for 4; -ene is the suffix for an alkene (double bond) and -oic acid is the ending for a carboxylic acid.  The base name is butenoic acid.   
  1. The chain is then numbered to give the carbonyl carbon the number 1.
  2. The structure is drawn so that the isomer (cis/trans) cannot be determined.
  3. The final name is
    traditional name:  2-butenoic acid
    or new form:  but-2-enoic acid.

 

12) 4-propylcyclohexane-1-carboxylic acid or 4-propylcyclohexanecarboxylic acid
  1. The longest chain of 6 is shown in red.  The carboxylic acid carbon is not included since it is not part of the ring.
  2. Hex- is root for 6.  Base name for the ring is cyclohexane.   
  1. The ring is numbered to give the carboxylic acid group the lowest number 1.
  2. There is a propyl group located at carbon 4.
  3. The final name is
    traditional name:  4-propylcyclohexane-1-carboxylic acid
    or new form: 4-propylcyclohexanecarboxylic acid

 

13) trans-2-ethyl-7-hydroxy-6-methyl-5-propyl-3-heptenoic acid or trans-2-ethyl-7-hydroxy-6-methyl-5-propylhept-3-enoic acid
  1. The longest carbon chain with the carboxylic acid group at carbon 1 that also includes the alcohol group is 7 carbons long.
  2. Hept- is the root for 7; -ene is the suffix for an alkene and -oic acid is the ending for a carboxylic acid.  The base name is heptenoic acid
  1. There is only one way to number the longest carbon chain giving the number 1 to the carboxylic acid carbon.
  2. Now locate the side groups:  2-ethyl, 5-propyl, 6-methyl, and 7-hydroxy
  1. The alkene located at carbon 3 must now be charaterized.  Since there is a hydrogen on both sides of the double bond, we can name the alkene using the cis/trans terminology.
  2. The alkene is trans since the non-hydrogen groups are across from each other.
  3. Put all the pieces together and the final name is
    traditional name:  trans-2-ethyl-7-hydroxy-6-methyl-5-propyl-3-heptenoic acid
    or new form:  trans-2-ethyl-7-hydroxy-6-methyl-5-propylhept-3-enoic acid.

 

14)  trans-2-methylcyclohexane-1-carboxylic acid or trans-2-methylcyclohexanecarboxylic acid
  1. The longest chain of 6 is circled.  The carboxylic acid carbon is not included since it is not part of the ring.
  2. Hex- is root for 6.  Base name for the ring is cyclohexane.   
  1. The ring is numbered to give the carboxylic acid group the lowest number 1.
  2. There is a methyl group located at carbon 2.
  3. The structure is drawn so that stereochemistry can be determined.  Since the two groups are on oposite sides of the ring, this is the trans form.
  4. The final name is
    traditional name:   trans-2-methylcyclohexane-1-carboxylic acid
    or new form: trans-2-methylcyclohexanecarboxylic acid.

 

15) (R)-5-bromohexanoic acid
  1. The longest carbon chain of 6 is circled.
  2. Hex- is root for 6; -oic acid is the ending for a carboxylic acid.  The base name is hexanoic acid
  1. The chain is then numbered to give the carboxylic acid carbon the number 1.
  2. There is a bromo group located at carbon 5.
  3. The name is now, 5-bromohexanoic acid.
  4. There is a stereogenic center at carbon 5.
  1. Priorities must be established using atomic numbers. Br (Z=35) is highest in priority. H (Z=1) is lowest in priority.
  2. Then, to decide the priorities for the different C (Z=6), look at the next adjacent atoms (which are highlighted in red in next sentence). CH3 (1+1+1=3) has a lower priority than CH2CH2CH2COOH (6+1+1=8) since 3 is less than 8.
  3. Holding the lowest priority atom in back, the other three are connected in increasing order.  Clockwise = R.
  4. The final name is (R)-5-bromohexanoic acid.