Chapter 23 – Review

23.1 Alcohols – Structure, Naming and Classification

  1. Is isobutyl alcohol primary, secondary, or tertiary? Explain. Check answer [1]
    From left to right, there are three carbon on the alkane straight chain with methyl groups emerging from carbon 2 and a hydroxyl group on carbon 3.
    (credit: Intro Chem: GOB, CC BY-NC-SA 3.0.)
  2. What is the longest continuous chain (LCC) in 2-ethyl-1-hexanol? What is taken as the LCC in naming the compound? Explain. Check answer[2]
  3. Name each alcohol and classify it as primary, secondary, or tertiary. Check answer[3]
    1. CH3CH2CH2CH2CH2CH2OH
    2. From left to right, there are six carbon on the alkane straight chain with a hydroxyl group on carbon 3.
      (credit: Intro Chem: GOB, CC BY-NC-SA 3.0.)
    3. From left to right, there are four carbons on the alkane straight chain with a methyl and hydroxyl group on carbon 2 and two bromine atoms on carbon 3.
      (credit: Intro Chem: GOB, CC BY-NC-SA 3.0.)

  4. Name each alcohol and classify it as primary, secondary, or tertiary.

    1. From left to right, there are five carbons on the alkane straight chain with a methyl group on carbon 2 and a hydroxyl group on carbon 3.
      (credit: Intro Chem: GOB, CC BY-NC-SA 3.0.)
    2. a 4 carbon chain with a methyl group at the 3rd carbon and an OH group at the 1st carbon
      (credit: Intro Chem: GOB, CC BY-NC-SA 3.0.)
    3. A pentagonal carbon structure is shown with two of the H atoms replaced by a hydroxyl atom and a methyl molecule.
      (credit: Intro Chem: GOB, CC BY-NC-SA 3.0.)
  5. Draw the structure for each alcohol. a. 3-hexanol b. 3,3-dimethyl-2-butanol c. cyclobutanol Check answer[4]
  6. Draw the structure for each alcohol.
    1. cyclopentanol
    2. 4-methyl-2-hexanol
    3. 4,5-dimethyl-3-heptanol
  7. What is a glycol? Check answer[5]
  8. Why is ethylene glycol so much more toxic to humans than propylene glycol?
  9. Draw the structure for each compound. Check answer[6]
    a. 1,5-pentanediol
    b. propylene glycol
  10. Draw the structure for each compound.
    1. 1,3-hexanediol
    2. glycerol

23.2 Physical Properties of Alcohols

  1. Why is ethanol more soluble in water than 1-hexanol? Check answer[7]
  2. Why does 1-butanol have a lower boiling point than 1-hexanol? Check answer[8]
  3. Arrange these alcohols in order of increasing boiling point: ethanol, methanol, and 1-propanol. Check answer[9]
  4. Which has the higher boiling point —butane or 1-propanol?
  5. Arrange these alcohols in order of increasing solubility in water: 1-butanol, methanol, and 1-octanol. Check answer[10]
  6. Arrange these compounds in order of increasing solubility in water: 1-butanol, ethanol, and pentane.
  7. Ethanol is used as a solvent for some drugs that are not soluble in water. Why is methanol not used in medicines?
  8. How does the boiling point and solubility change if more OH groups are included in a molecule? Why?

23.3 Formation of Alcohols

  1. From what alkene is ethanol made? Draw its condensed structural formula. Check answer[11]
  2. Can methanol be made from an alkene? Explain.
  3. 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. Check answer[12]
    1. 2-methylpropene
    2. 1-butene
    3. 2-methyl-1-pentene
    4. 2-methyl-2-pentene
  4. Alcohols can be made from alkyl halides, aldehydes and ketones, and esters.  Provide a description or example of each reaction.

23.4 Reactions of Alcohols

  1. Name the three major types of chemical reactions of alcohols. Check answer[13]

  2. Why do tertiary alcohols not undergo oxidation? Can a tertiary alcohol undergo dehydration?

  3. Draw the structure of the product for each reaction.

    1. Reaction of 2 methyl 2 propanol under excess concentrated sulfuric acid at 180 degrees celsius.
      (credit: Intro Chem: GOB, CC BY-NC-SA 3.0).
    2. Reaction of 2 pentanol with potassium dichromate under acidic conditions.
      (credit: Intro Chem: GOB, CC BY-NC-SA 3.0).

      Check answer[14]

  4. Write an equation for the dehydration of 2-propanol to yield each compound type. Check answer[15]

    1. an alkene
    2. an ether

  5. Draw the structure of the alkene formed by the dehydration of cyclohexanol.

    Classify each conversion as oxidation, dehydration, or hydration (only the organic starting material and product are shown): Check answer[16]

    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. What does a positive result from the Tollen’s test, Fehling test and Benedict test look like? Check answer[17]
  8. For each compound, identify if the test result will be positive or negative given the listed test.
    1. 2-propanol – Tollen’s test
    2. 2-methyl-2-pentanol – Benedict Test
    3. cyclopentanol – Fehling Test
  9. Draw the major product from the dehydration of each compound (assume alkene formation).
    1. 2-methyl-2-pentanol
    2. 2-chlorocyclopentanol
    3. 2-methyl-4-octanol
  10. Draw the product of esterification of ethanol and ethanoic acid.
 23.5 Phenols
  1. How do phenols differ from alcohols in terms of structure and properties? Check answer[18]
  2. How do phenols differ in properties from aromatic hydrocarbons? Check answer[19]
  3. Name each compound. Check answer[20]
    1. a benzene structure with a nitro group at the 1st carbon and an OH group at the 2nd carbon
      (credit: Intro Chem: GOB, CC BY-NC-SA 3.0).
    2. a benzene structure with a bromo group at the 4th carbon and an OH group at the 1st carbon
      (credit: Intro Chem: GOB, CC BY-NC-SA 3.0).

  4. Name each compound.

    1. a benzene structure with an OH group at the 1st carbon and a chloro group at the 3rd carbon
      (credit: Intro Chem: GOB, CC BY-NC-SA 3.0).
    2. a benzene structure with an OH group at the 1st carbon and an isopropyl group at the 2nd carbon
      (credit: Intro Chem: GOB, CC BY-NC-SA 3.0).
  5. Draw the structure for each compound. Check answer[21]
    a) m-iodophenol
    b) p-methylphenol (p-cresol)
  6. Draw the structure for each compound.
    1. 2,4,6-trinitrophenol (picric acid)
    2. 3,5-diethylphenol

23.6 Ethers

  1. 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. a 3 carbon chain with an OH group at the 2nd carbon
      (credit: Intro Chem: GOB, CC BY-NC-SA 3.0.)
    3. a phenol structure
      (credit: Intro Chem: GOB, CC BY-NC-SA 3.0.)
    4. an ether compound with a methyl on one side and a isopropyl group on the other side.
      (credit: Intro Chem: GOB, CC BY-NC-SA 3.0.)
  2. Identify each compound as an alcohol, a phenol, or an ether. Classify any alcohols as primary, secondary, or tertiary. Check answer[22]

    1. CH3CH2OCH2CH3
    2. a 3 carbon chain with a methyl and OH group both at the 2nd carbon
      (credit: Intro Chem: GOB, CC BY-NC-SA 3.0.)
    3. a benzene group with an OH group at the 1st carbon and a chloro group at the 4th carbon
      (credit: Intro Chem: GOB, CC BY-NC-SA 3.0.)
    4. a 5 carbon chain with an OH group at the 2nd carbon
      (credit: Intro Chem: GOB, CC BY-NC-SA 3.0.)
  3. Why does ethoxyethane (CH3CH2OCH2CH3) have a much lower boiling point than 1-butanol  (CH3CH2CH2CH2OH)? Check answer[23]
  4. Which is more soluble in water—methoxyethane (CH3CH2OCH3) or 1-butanol (CH3CH2CH2CH2OH)? Explain. Check answer[24]
  5. How can ethanol give two different products when heated with sulfuric acid? Name these products. Check answer[25]
  6. Which of these ethers is isomeric with ethanol—CH3CH2OCH2CH3, CH3OCH2CH3, or CH3OCH3?
  7. Name each compound. Check answer[26]
    1. CH3OCH2CH2CH3
    2. The oxygen atom is bonded to an isopropyl group and an ethyl group.
      (credit: Intro Chem: GOB, CC BY-NC-SA 3.0).
  8. Name each compound.
    1. CH3CH2CH2CH2OCH3
    2. CH3CH2OCH2CH2CH3
  9. Draw the structure for each compound. Check answer[27]
      1. methoxyethane
      2. ethoxytert-butane

23.7 Thiols

  1. What is the functional group of a thiol? Write the condensed structural formula for ethanethiol (ethyl mercaptan). Check answer[28]
  2. What is the functional group of a disulfide? Write the condensed structural formula for dipropyl disulfide. Check answer[29]
  3. A common natural gas odourant is tert-butyl mercaptan. What is its condensed structural formula? Check answer[30]
  4. Write the equation for the oxidation of ethanethiol to diethyl disulfide.

Links to Enhanced Learning

Create your own organic nomenclature quiz to identify, name and draw alcohols and ethers using Organic Nomenclature (orgchem101.com).  You can customize the types of questions you receive and get instant feedback.

Attribution & References

Except where otherwise noted, this page (including images in solutions) is written and adapted by David Wegman and Samantha Sullivan Sauer from

  1. primary; the carbon atom bearing the OH group is attached to only one other carbon atom ↵
  2. 7 carbon atoms; the 6-atom chain includes the carbon atom bearing the OH group ↵
  3. a) 1-hexanol; primary b) 3-hexanol; secondary c) 3,3-dibromo-2-methyl-2-butanol; tertiary ↵
  4. a)Structural formula of 3-hexanol.b)Structural formula of 3,3-dimethyl-2-butanol.c)Structural formula of cyclobutanol. ↵
  5. an alcohol with two OH groups on adjacent carbon atoms ↵
  6. a. HOCH2CH2CH2CH2CH2OH b.a 3 carbon chain with an OH group at the 1st and 2nd carbon. ↵
  7. Ethanol has an OH group and only 2 carbon atoms; 1-hexanol has one OH group for 6 carbon atoms and is thus more like a (nonpolar) hydrocarbon than ethanol is. ↵
  8. The molar mass of 1-hexanol is greater than that of 1-butanol. ↵
  9. methanol < ethanol < 1-propanol ↵
  10. 1-octanol < 1-butanol < methanol ↵
  11. ethylene; CH2=CH2 ↵
  12. a. 2-methyl-2-propanol, b. 2-butanol, c. 2-methyl-2-pentanol, d. 2-methyl-2-pentanol ↵
  13. dehydration, oxidation, and esterification ↵
    1. Structural formula of isobutylene.
    2. Structural formula of 2 pentanone.
    ↵

  15. a. CH3CHOHCH3 → CH3COCH3 + H2O (under conditions of conc H2SO4 180∘C excess acid)

    b. 2 CH3CHOHCH3 → (CH3)2CHOCH(CH3)2 + H2O (under conditions of conc H2SO4 140∘C, excess alcohol)

    ↵

  16. a. oxidation, b. dehydration, c. hydration ↵
  17. Tollens - silver mirror finish, Fehling - red precipitate, Benedict - red precipitate ↵
  18. Phenols have an OH group attached directly to an aromatic ring. Phenols are weakly acidic. ↵
  19. Phenols have an OH group and are somewhat soluble in water. ↵
  20. 1) o-nitrophenol 2) p-bromophenol ↵
  21. a)a benzene structure with an OH group at the 1st carbon and an iodo group at the 3rd carbonb)a benzene structure with an OH group at the 1st carbon and a methyl group at the 4th carbon. ↵
  22. a. ether b. tertiary alcohol c. phenol d. secondary alcohol ↵
  23. Ethoxyethane has no intermolecular hydrogen bonding because there is no OH group; 1-butanol has an OH and engages in intermolecular hydrogen bonding. ↵
  24. methoxyethane (three carbon atoms, one oxygen atom) is more soluble in water than 1-butanol (four carbon atoms, one oxygen atom), even though both can engage in hydrogen bonding with water. ↵
  25. Intramolecular (both the H and the OH come from the same molecule) dehydration gives ethene; intermolecular (the H comes from one molecule and the OH comes from another molecule) dehydration gives ethoxyethane. ↵
  26. 1) methoxypropane 2) ethoxyisopropane ↵
  27. 1) CH3OCH2CH3 2)a oxygen separating an ethyl group and a tert-butyl group ↵
  28. SH; CH3CH2SH ↵
  29. –S–S–; CH3CH2CH2SSCH2CH2CH3 ↵
  30. (CH3)3CSH ↵

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Organic and Biochemistry Supplement to Enhanced Introductory College Chemistry Copyright © 2024 by Gregory Anderson; Caryn Fahey; Adrienne Richards; Samantha Sullivan Sauer; David Wegman; and Jen Booth is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.

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