Skip to main content
Chemistry LibreTexts

14.E: Organic Compounds of Oxygen (Exercises)

[ "article:topic", "showtoc:no" ]
  • Page ID
    41731
  • Additional Exercises

    1. Describe two ways that ethanol can be prepared. Which method is used to produce alcoholic beverages?

    2. Give the structure of the alkene from which isopropyl alcohol is made by reaction with water in an acidic solution.

    3. Ethanol is used as a solvent for some drugs that are not soluble in water. Why is methanol not used in medicines?

    4. Give the structure of the alkene that is made from tert-butyl alcohol [(CH3)3COH] by reaction with water in an acidic solution.

    5. Classify each conversion as oxidation, dehydration, or hydration (only the organic starting material and product are shown):

      1. CH3OH → HCHO
      2. CH3CHOHCH3 → CH3CH=CH2
      3. CH2=CHCH2CH3 → CH3CHOHCH2CH3
    6. Classify each conversion as oxidation, dehydration, or hydration (only the organic starting material and product are shown.):

      1. CH3CHOHCH3 → CH3COCH3
      2. HOOCCH=CHCOOH → HOOCCH2CHOHCOOH
      3. 2 CH3OH → CH3OCH3
    7. Why is methanol so much more toxic to humans than ethanol?

    8. Each of the four isomeric butyl alcohols is treated with potassium dichromate (K2Cr2O7) in acid. Give the product (if any) expected from each reaction.

    9. Draw the structures and give IUPAC names for the four isomeric aldehydes having the formula C5H10O.

    10. Write an equation for the reaction of phenol with aqueous NaOH.

    11. Write an equation for the ionization of phenol in water.

    12. Draw the structures and give the common and IUPAC names for the three isomeric ketones having the formula C5H10O.

    13. As we shall see in Chapter 16 "Carbohydrates", 2,3-dihydroxypropanal and 1,3-dihydroxyacetone are important carbohydrates. Draw their structures.

    14. Glutaraldehyde (pentanedial) is a germicide that is replacing formaldehyde as a sterilizing agent. It is less irritating to the eyes, the nose, and skin. Write the condensed structural formula of glutaraldehyde.

    15. Why does the oxidation of isopropyl alcohol give a ketone, whereas the oxidation of isobutyl alcohol gives an aldehyde?

    16. Identify each compound as an alcohol, a phenol, or an ether. Classify any alcohols as primary (1°), secondary (2°), or tertiary (3°).

      1. CH3CH2CH2OH
      2. 16b.jpg
      3. 16c.jpg
      4. 16d.jpg
    17. Identify each compound as an alcohol, a phenol, or an ether. Classify any alcohols as primary, secondary, or tertiary.

      1. CH3CH2OCH2CH3
      2. 17b.jpg
      3. 17c.jpg
      4. 17d.jpg
    18. Tell whether each compound forms an acidic, a basic, or a neutral solution in water.

      1. 18a.jpg
      2. 18b.jpg
      3. 18c.jpg
    19. When water is added to ethylene in the presence of an acid catalyst, only one product—ethanol—is possible. However, when water is added to propylene, two products are possible—1-propanol and 2-propanol—but only 2-propanol is formed. In 1870, the Russian chemist Vladimir V. Markovnikov proposed a rule to predict the products of such reactions: Considering water to be HOH, the hydrogen atom of water goes on the carbon atom (of the two involved in the double bond) that has the most hydrogen atoms already bonded to it. The OH group goes on the carbon atom with fewer hydrogen atoms. Use Markovnikov’s rule to predict the product of the addition of water to each compound.

      1. 2-methylpropene
      2. 1-butene
      3. 2-methyl-1-pentene
      4. 2-methyl-2-pentene
    20. Ethyl alcohol, like rubbing alcohol (isopropyl alcohol), is often used for sponge baths. What property of alcohols makes them useful for this purpose?

    21. In addition to ethanol, the fermentation of grain produces other organic compounds collectively called fusel oils (FO). The four principal FO components are 1-propanol, isobutyl alcohol, 3-methyl-1-butanol, and 2-methyl-1-butanol. Draw a structure for each. (FO is quite toxic and accounts in part for hangovers.)

    22. Draw and name the isomeric ethers that have the formula C5H12O.

    23. Menthol is an ingredient in mentholated cough drops and nasal sprays. It produces a cooling, refreshing sensation when rubbed on the skin and so is used in shaving lotions and cosmetics. Thymol, the aromatic equivalent of menthol, is the flavoring constituent of thyme.

      23.jpg
      1. To what class of compounds does each belong?
      2. Give an alternate name for thymol.
    24. Write the equation for the production of ethanol by the addition of water to ethylene. How much ethanol can be made from 14.0 kg of ethylene?

    25. Methanol is not particularly toxic to rats. If methanol were newly discovered and tested for toxicity in laboratory animals, what would you conclude about its safety for human consumption?

    26. The amino acid cysteine has the formula HSCH2CH(NH2)COOH. What is the sulfur-containing functional group in the cysteine molecule?

    27. The amino acid methionine has the formula CH3SCH2CH2CH(NH2)COOH. What functional groups are in methionine?

    28. Tetrahydrocannabinol is the principal active ingredient in marijuana. What functional groups are present in this molecule?

      28.jpg

    Answers

    1. addition of water to ethylene; fermentation (for beverages)

     
    1. Methanol is too toxic.

     
    1.  

      1. oxidation
      2. dehydration
      3. hydration
     
    1. Methanol is oxidized in the body to toxic formaldehyde; ethanol is oxidized to the less toxic acetaldehyde.

     
    1. 9.jpg
     
    1. C6H5OH + H2O → C6H5O + H3O+

     
    1. 13.jpg
     
    1. Isopropyl alcohol is a secondary alcohol, whereas isobutyl alcohol is a primary alcohol.

     
    1.  

      1. ether
      2. tertiary alcohol
      3. phenol
      4. secondary alcohol
     
    1.  

      1. tert-butyl alcohol
      2. 2-butanol
      3. 2-methyl-2-pentanol
      4. 2-methyl-2-pentanol
     
    1. 21.jpg
     
    1.  

      1. menthol: alcohol; thymol: phenol
      2. 2-isopropyl-5-methylphenol
     
    1. It might be ruled safe until tested on humans.

     
    1. sulfide, amino, and carboxylic acid