Orgo 10.1-10.6

Card Set Information

Orgo 10.1-10.6
2013-12-19 20:58:04
CHM 202
Show Answers:

  1. Characteristics of hydroxyl groups 
    1) hybridization and bond angle
    2) how does the bond angle compare to the bond angle of water 
    3) why

    The O-H bond lengths are about the same in water and methanol, but the C-O is __, reflecting the __ of carbon compared to hydrogen.
    • 1) sp3/ 108.9
    • 2) it is larger 
    • 3) because the methyl group is much larger than a hydrogen atom

    • larger
    • larger covalent radius
  2. One way of organizing the alcohol family is to classify each alcohol according to the type of __: the one bonded to the -OH group. If this carbon atom is __(bonded to one other carbon atom), the compound is a __.
    • carbinol carbon atom
    • primary
    • primary alcohol
  3. A __ has the -OH group attached to the __ carbon atom, and a __ has it bonded to a __ carbon.
    • secondary x2
    • tertiary x2
  4. Compounds with a hydroxyl group bonded directly to an aromatic ring are called __, which have many properties similar to those of alcohols, while other properties derive from their __.
    • phenols
    • aromatic character
  5. IUPAC Naming
    1) carries the __ suffix, together with a __ to give the hydroxyl's location. 
    2) What is the first rule for naming.
    • 1) ol, number
    • 2) find the longest carbon chain bearing the -OH group
  6. The alcohol functional group takes __ over __ and __, so the chain is numbered in order to give the lowest possible number to the carbon atom bonded to the __ group
    • precedence
    • double
    • triple bonds
    • -OH
  7. The -OH functional group is named as a __ when it appears on a structure with a higher-priority functional group or when the structure is too difficult to name as a simple alcohol..
    hydroxy substituent
  8. Alcohols with two -OH groups are called __ or __. They are named like other alcohols except that the suffix __ is used and two numbers are needed.
    • diols
    • glycols
    • diol
  9. The term glycol generally means __, or __, with its two hydroxyl groups on adjacent carbon atoms. __ are usually synthesized by the hydroxylation of alkenes, using peroxyacids, osmium tetroxide, or potassium permanganate.
    • 1,2-diol
    • vicinal diol
    • glycols
  10. Because the phenol structure involves a benzene ring, the terms __ (1,2-disubbed), __ (1,3-disubbed), and __ (1,4-disubbed) are often used in the common names. 

    The methylphenols are called __, while the names of the __ are based on their historical uses and sources rather than their structures.
    • ortho
    • meta
    • para

    • cresols
    • benzenediols
  11. Most of the common alcohols, up to about 11 or 12 carbons, are __ at room temp.

    True or False: Lower molecular weight alcohols are liquids.

    Such large difficerences in BPs of ethyl alcohol (78) and propane alochol (-42) suggests that __ are attracted to each other much more strongly than __ molecules. Two important intermolecular forces are responsible: _ and __.


    ethyl molecules

    propane molecules

    H bonding

    d-d interactions
  12. __ is the major intermolecular attraction responsible for ethanol's hight BP. The hydroxyl hydrogen of ethanol is strongly __ by its bond to oxygen and it forms a __ with a pair of nonbonding electrons from the oxygen atom of another alocohol molecule.
    • h bonding
    • polarized
    • hydrogen bond
  13. Ethers have __ bonded to their oxygen atoms, so they have no O-H hydrogen atoms to form hydrogen bonds. __ have a strength of about 21 kJ per mole: weaker than typical __ of 300-500 kJ, but much stronger than __.
    two alkyl groups

    hydrogen bonds

    covalent bonds

    dipole-dipole attractions
  14. __ also contribute to the relatively __ of alcohols and ethers. The polarized C-O and H-O bonds and the nonbonding electrons add to produce a __ of 1.69 D in ethanol, compared with a __ of only 0.08 D in propane. In liquid ethanol, the positive and negative ends of these dipoles align to produce attractive interactions.
    • dipole-dipole attractions
    • high BPs
    • dipole moment x2
  15. __ are clearly much stronger intermolecular attractions than __.
    hydrogen bonds

    dipole-dipole attractions
  16. Walter and alcohols have similar properties because they all contain __ that can form H bonds. Alcohols form hydrogen bonds with water, and several of the lower-MW alcohols are __ (soluble in any proportions) with water.
    • hydroxyl groups
    • miscible
  17. Similarly, alcohols are much better __ than __ for polar substances. Significant amounts of ionic compounds such as NaCl can dissolve in some of the lower alcohols. We call the hydroxyl group __, meaning "water loving" because of its affinity for water and other polar substances
    • solvents
    • hydrocarbons
    • hydrophilic
  18. The alcohol's alkyl group is called __ because it acts like an alkane: it disrupts the network of hydrogen bonds nad dipole dipole attractions of a polar solvent such as water. The alkyl group makes the alcohol less __, yet it lends solubility in nonpolar organic solvents. As a result, most alcohols are miscible with a wide range of nonpolar organic solvents.
    • hydrophobic
    • hydrophilic
  19. True or False: The water solubility increases as the alkyl group becomes larger.

    Explain this.
    False: decreases as the alkyl group becomes larger

    • alcohols with one, two, or three carbon alkyl groups are miscible
    • a four carbon is large enough that some isomers are not miscible, but tert butyl alcohol is miscible.

    IN GENERAL: a hydroxyl gorup can carry about 4 carbon atoms into water
  20. Like the hydroxyl proton of water, the hydroxyl proton of an alcohol is __. A strong base can remove the hydroxyl proton to give an __.
    • weakly acidic
    • alkoxide ion
  21. The acidities of alcohols vary widely, from alcohols that are about as acidic as water to some that are much less acidic. The __ of an alcohol is defined by the __.
    • acid-dissociation constant, Ka
    • equilibrium
  22. The __ constants for alcohols vary according to their structure, from about 10^-16 for __down to about 10^-18 for most __.

    Explain the trend in acidity.
    • acid-dissociation constants
    • methanol 
    • tertiary alcohols

    the acidity decreases as the substitution on the alkyl group increases, because a more highly substituted alkyl group inhibits solvation of the alkoxide ion, decreasing the stability of the alkoxide ion and driving the dissociation equilibrium toward the left
  23. __ are strong nucleophiles and strong bases. When an __ is needed in a synthesis, it is often formed by th reaction of __ or __ with the alcohol. This is an __, with the metal being __ and the H ion __ form hydrogen gas. __ bubbles out of the solution, leaving the sodium or potassium salt of the alkoxide ion.
    • alkoxide ions x2
    • sodium 
    • potassium metal
    • oxidation-reduction
    • oxidized
    • reduced
    • hydrogen
  24. The more acidic alcohols, like methanol and ethanol, react rapidly with sodium to form __ and __. __ react more slowly. __ react very slowly with sodium. __ is often used with secondary and tertiary alcohols because it is __, and the reaction can be completed in convenient amount of time.
    • sodium methoxide
    • sodium ethoxide
    • secondary alcohols
    • tertiary alcohols
    • potassium
    • more reactive than sodium
  25. Some alcohols react slowly with both __ and __ In these cases, a useful alternative is __, often is tetrahydrofuran (THF) solution. __ reacts quickly to form the __, even with different compounds.
    • Na
    • K
    • sodium hydride x2
    • alkoxide
  26. True or False: Phenols have the same acidity as cyclohexanols.
    • False:
    • Phenols are nearly 100 million times more acidic than cyclohexanol
  27. Cyclohexanol is a typical __, with a typical acid-dissociation constant for an __. There must be something special about phenol that makes it unusually __. The __ is more stable than a typical __ because the negative charge is not confined to the oxygen atom but is delocalized over the __ and __ of the ring.
    • secondary alcohol
    • alcohol
    • acidic
    • phenoxide ion
    • oxygen
    • three carbon atoms
  28. A large part of the negative charge in the __ still resides on the __, since it is the most __ of the four atoms sharing the charge. But the ability to spread the negative charge over four atoms rather than concentrating it on just one atom produces a more stable ion. The reaction of  phenol with __ is __.
    • resonance hybrid
    • oxygen atom
    • electronegative 
    • sodium hydroxide
    • exothermic
  29. __ are prepared simply by adding hte __ to an aqueous solution of __ or __. There is no need to use __ or __. __ was once called __ because of its ability to __ common bases.
    • phenoxide anions
    • sodium hydroxide
    • potassium hydroxide
    • sodium 
    • potassium metal
    • phenol
    • carbolic acid
    • neutralize