1. Chapter 14 Aldehydes, Ketones, and Chiral Molecules
14.1
Aldehydes and Ketones
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2. Carbonyl Group in Aldehydes and Ketones
A carbonyl group
In an aldehyde is attached to at least one H atom.
In a ketone is attached to two carbon groups.
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3. Naming Aldehydes An aldehyde
Has an IUPAC name in which the -e in the alkane name is changed to -al.
Has a common name for the first four aldehydes that use the prefixes form­ (1C), acet­ (2C), propion­ (3C), and butyr­ (4C), followed by aldehyde.
O O O
║ ║ ║
H−C−H CH3−C−H CH3−CH2−C−H
methanal ethanal propanal
(formaldehyde) (acetaldehyde) (propionaldehyde)

4. Naming Aldehydes Copyright © 2007 by Pearson Education, Inc.
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5. Aldehydes in Flavorings
Several naturally occurring aldehydes are used as flavorings for foods and fragrances.
Benzaldehyde
(almonds)
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Cinnamaldehyde (cinnamon)

6. Naming Ketones Ketones are named
In the IUPAC system by replacing the -e in the alkane name with ­one. The carbonyl carbon is indicated by a number.
With a common name by indicating the alkyl groups attached to the carbonyl group in alphabetical order
followed by ketone.
O O
║ ║
CH3−C−CH CH3−C−CH2−CH3
propanone butanone
(dimethyl ketone) (ethyl methyl ketone)

7. Ketones in Common Use Butter flavoring Nail polish remover, Solvent
Propanone, Dimethylketone, Acetone
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8. Learning Check Classify each as 1) aldehyde or 2) ketone. O O || ||
|| ||
A. CH3—CH2—C—CH B. CH3—C—H
CH O
| ||
C. CH3—C—CH2—C—H D. |
CH3

9. Solution
A. 2) ketone
B. 1) aldehyde
C. 1) aldehyde
D. 2) ketone

10. Learning Check
Classify each as an aldehyde (1), ketone (2), alcohol (3),
or ether (4). O ║
A. CH3─CH2─C─CH3 B. CH3─O─CH3
CH O OH
│ ║ │
C. CH3─C─CH2─C─H D. CH3─CH─CH3 │
CH3

11. Solution Classify each as an aldehyde (1), ketone (2),
alcohol (3), or ether (4). O ║
A. CH3─CH2─C─CH3 B. CH3─O─CH3
(2) ketone (4) ether
CH O OH
│ ║ │
C. CH3─C─CH2─C─H D. CH3─CH─CH3 │
CH3
(1) aldehyde (3) alcohol

12. Learning Check Name each of the following: O ║ 1. CH3─CH2─CH2─CH2─C─H
2. Cl─CH2─CH2─C─H
3. CH3─CH2─C─CH3

13. Solution O ║ 1. CH3─CH2─CH2─CH2─C─H pentanal
2. Cl─CH2─CH2─C─H 3-chloropropanal
3. CH3─CH2─C─CH3 2-butanone;
ethyl methyl ketone

14. Learning Check Name the following compounds. O ||
A. CH3—CH2—CH2—C—CH B.
CH O
| ||
C. CH3—C—CH2—C—H |
CH3

15. Solution A. 2-pentanone; methyl propyl ketone B. cyclohexanone
C, 3,3-dimethylbutanal

16. Learning Check Draw the structural formulas for each:
A. 4-methylpentanal
B. 2,3-dichloropropanal
C. 3-methyl-2-butanone

17. Solution CH3 O │ ║ A. 4-methylpentanal CH3─CH─CH2─CH2─C─H Cl O │ ║
│ ║
B. 2,3-dichloropropanal Cl─CH2─CH─C─H
CH3 O
C. 3-methyl-2-butanone CH3─CH─C─CH3

18. Chapter 14 Aldehydes, Ketones, and Chiral Molecules
14.2
Physical Properties
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Publishing as Benjamin Cummings

19. Polar Carbonyl Group The polar carbonyl group
Provides dipole-dipole interactions.
+  + -
C=O C=O
Does not have H on the oxygen atom.
Cannot form hydrogen bonds.

20. Boiling Points Aldehydes and ketones have Polar carbonyl groups (C=O).
+ -
C=O
Attractions between polar groups.
+  + -
C=O C=O
Higher boiling points than alkanes and ethers of similar mass.
Lower boiling points than alcohols of similar mass.

21. Comparison of Boiling Points58
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22. Learning Check Select the compound in each pair that would have the
Higher boiling point.
A. CH3—CH2—CH3 or CH3—CH2—OH B.
C. CH3—CH2—OH or CH3—O—CH3

23. Solution
A. CH3—CH2—OH B.
C. CH3—CH2—OH

24. Solubility in Water
The electronegative O atom of the carbonyl group in aldehydes and ketones forms hydrogen bonds with water.
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25. Learning Check Indicate if each is soluble or insoluble in water.
A. CH3—CH2—CH3
B. CH3—CH2—OH O ||
C. CH3—CH2—CH2—C—H
D. CH3—C—CH3

26. Solution A. CH3—CH2—CH3 insoluble B. CH3—CH2—OH soluble O ||
C. CH3—CH2—CH2—C—H soluble
D. CH3—C—CH soluble

27. Chapter 14 Aldehydes, Ketones and Chiral Molecules
14.3
Oxidation and Reduction
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28. Oxidation Aldehydes are easily oxidized to carboxylic acids. O O
CH3—C—H CH3—C—OH
Acetaldehyde Acetic acid

29. Tollens’ Test
Tollens’ reagent, which contains Ag+, oxidizes aldehydes, but not ketones.
Ag+ is reduced to metallic Ag, which appears as a “mirror” in the test tube.
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30. Benedict’s Test In the Benedict’s Test,
Cu2+ reacts with aldehydes that have an adjacent OH group.
Aldehydes are oxidized to carboxylic acids.
Cu2+ is reduced to give Cu2O(s).
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31. Learning Check Write the structure and name of the oxidized product
when each is mixed with Tollens’ reagent.
1. butanal
2. acetaldehyde
3. ethyl methyl ketone

32. Solution 1. butanal O || CH3—CH2—CH2—C—OH butanoic acid
2. acetaldehyde O
CH3—C—OH
acetic acid
3. ethyl methyl ketone None. Ketones are not
oxidized by Tollen’s reagent.

33. Chapter 14 Aldehydes, Ketones and Chiral Molecules
14.4
Addition Reactions
| +  +  |
—C=O X—Y —C—O—X | Y

34. Addition Reactions When a polar molecule adds to the carbonyl group of
an aldehyde or ketone
The negative part of the added molecule bonds to the positive carbonyl carbon.
The positive part of the added molecule bonds to the negative carbonyl oxygen.
| +  +  |
—C=O X—Y — C—O—X | Y

35. Acetal Formation
Alcohols add to the carbonyl group of aldehydes and ketones.
The addition of two alcohols forms acetals.
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36. Hemiacetal Formation
The addition of one alcohol to an aldehyde or ketone forms an intermediate called a hemiacetal.
Usually, hemiacetals are unstable and difficult to isolate.
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37. Cyclic Hemiacetals
A stable cyclic hemiacetal forms when the C=O group and the —OH are both part of a five- or
six-atom carbon compound.
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38. Learning Check Identify each as a 1) hemiacetal or 2) acetal. O—CH3 |
A. CH3—CH2—C—H OH
O—CH2CH3
B. CH3—CH2—C—CH2—CH3

39. Solution O—CH3 | A. CH3—CH2—C—H 1) hemiacetal OH O—CH2CH3
B. CH3—CH2—C—CH2—CH ) acetal

40. Learning Check
Draw the structure of the acetal formed by adding CH3OH to butanal.

41. Solution O—CH3 | CH3—CH2—CH2—C—H |
Draw the structure of the acetal formed by adding CH3OH to butanal.
O—CH3 |
CH3—CH2—CH2—C—H |

42. Chapter 14 Aldehydes, Ketones, and Chiral Molecules
14.5
Chiral Molecules
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Publishing as Benjamin Cummings

43. Chiral Compounds Chiral compounds
Have the same number of atoms arranged differently in space.
Have one or more chiral carbon atoms bonded to four different groups.
Are mirror images like your hands. Try to superimpose your thumbs, palms, back of hands, and little fingers.
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44. Mirror Images The mirror images of
Chiral compounds cannot be superimposed.
Two compounds of bromochloroiodomethane can align the H and I atoms, which places the Cl and Br atoms on opposite sides.
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45. Achiral Structures are Superimposable
When the mirror image of an achiral structure is rotated, the structure can be aligned with the initial structure. Thus this mirror image is superimposable.
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46. Some Everyday Chiral and Achiral Objects

47. Learning Check
Identify each as a chiral or achiral compound.

48. Solution Identify each as a chiral or achiral compound.
chiral achiral chiral

49. Fischer Projections A Fischer projection
Is a 2-dimensional representation of a 3-dimensional molecule.
Places the most oxidized group at the top.
Uses vertical lines in place of dashes for bonds that go back.
Uses horizontal lines in place of wedges for bonds that come forward.

50. Drawing Fischer Projections
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51. D and L Notations
By convention, the letter L is assigned to the structure with the —OH on the left.
The letter D is assigned to the structure with the —OH on the right.
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52. Learning Check Indicate whether each pair is a mirror image that
cannot be superimposed.

53. Solution Indicate whether each pair is a mirror image that
cannot be superimposed
Yes No