Figure 4-97. Selected carboxylic acids with names.
The most widely used carboxylic acid, acetic acid, is manufactured on a very large scale of approximately 5 million tons annually. Pure acetic acid containing less than 1% water is often called glacial
acetic acid. This name comes from the fact that pure acetic acid freezes out into an ice-like crystalline mass on cooling slightly below room temperature (at ~16 o
C). 4.6.5. Exercises.
1. What is a functional group in organic chemistry? Give examples of functional groups with their names. [Answer: See 4.6.1]
2. Why is methanol a liquid at room temperature, whereas methane, formaldehyde, and even chloromethane are gases? [Answer: See 4.6.2]
3. Why is methanol toxic? What is the reason for the blindness as one of the first symptoms of methanol poisoning? How does the ethanol treatment of methanol poisoning work? [Answer: See 4.6.2]
4. There are four bottles, each containing a different liquid: methanol, ethanol, acetic acid, and gasoline (a mixture of alkanes). Find out which liquid is in which bottle. You have water, ice, and plenty of empty bottles and test tubes for mixing the liquids, if necessary. You do not have anything else. Smelling the liquids is prohibited to avoid the risk of irritation of the respiratory organs, especially by vapors of acetic acid. Answer
5. Draw chemical structures for the following compounds: (a) isopropanol (rubbing alcohol); (b) methanol (wood alcohol); (c) phenol; (d) para
-nitrophenol; (e) formaldehyde; (f) 3-chlorobenzaldehyde; (g) 3-methylpentanal; (h) formic acid; (i) benzoic acid; (j) acetic acid; (k) terephthalic acid; (l) butanoic acid; (m) 2,2-dimethylpropanoic acid; (n) potassium stearate; (m) glycerol; (n) methyl isopropyl ketone; (o) acetone.
6. Draw the structure of ethylene glycol. What is the danger of ethylene glycol, especially for animals and children? [Answer: See 4.6.2]
7. What is soap? How does soap work? Why does soap lose activity in hard water? Do you think adding diluted HCl to soapy water would enhance or diminish its cleaning ability? Answer
8. Draw the structure of benzoic acid dimer. Hint
9. What is the hybridization of the carbon atom in (a) methane; (b) methanol; (c) formaldehyde; (d) formic acid? Answer
10. What is the alternative name for the aldehyde group? Answer
11. May formic acid be viewed as an aldehyde? Answer
12. Old samples of phenol are pink or red in color, often appearing as crystals in a syrupy liquid. Why? Pure phenol is a white crystalline solid. [Answer: See 4.6.2]
13. What is (a) wood alcohol; (b) formalin; (c) carbolic acid; (d) sugar of lead? Answer
14. Formulations containing large quantities of phenol are widely used for permanent treatment of ingrown toenails, certainly not life-threatening yet painful and annoying condition. What do you think of the role of phenol in this treatment, called phenol cauterization
or phenol matricectomy