Download Alcohol Worksheet Key

CHE 261
Alcohol Worksheet
Name ___________________
1.
Name the following compounds:
OH
OH
trans-3-propyl-4-hexen-2-ol
2.
(1S)-2-cyclohexen-1-ol
Draw the following compounds:
3-mercapto-2,5-pentandiol
sec-butyl alcohol
OH
OH
OH
SH
3.
Rank the following compounds in order of increasing acidity and justify your answer.
Cl
1
OH
SH
OH
3
2
1 < 3 < 2,
Thiols are more acidic than alcohols. The chlorine on 3 increases the acidity of 3
through the inductive effect.
4.
Rank the following compounds in order of increasing solubility in water and justify your
answer.
OH
OH
OH
1
2
OH
3
2 < 1 < 3,
3 has 4 carbons and therefore is most soluble in water. 1 and 2 have the same
number of carbons, but 1 has 2 alcohol groups and is therefore more soluble.
5.
Rank the following compounds in order of increasing boiling point and justify your
answer.
Cl
OH
SH
OH
1
3
2
2 < 1 < 3,
1 and 3 exhibit H-bonding, but 3 has a higher molecular weight. It has the highest
boiling point. 2 has the lowest boiling point because it doesn’t exhibit H-bonding.
6.
Draw the resonance structures of the conjugate base of 4-chlorophenol. Would you
expect 4-chlorophenol to be more or less acidic than 3-chlorophenol? Explain. Why is the
positioning of the chloro group important (whether it is at position 2, 3, or 4)?
O
O
O
O
Cl
Cl
Cl
Cl
4-chlorophenol is more acidic than 3-chlorophenol due to the inductive effect of the chlorine at
position 4. The negative charge is not delocalized onto postions 3 or 5, so electron withdrawing
groups at position 3 and 5 will have very little effect on the acidity of the phenol.
7.
For the following acid-base reactions, predict the products. Label the acid (A), base (B),
conjugate acid (CA), and conjugate base (CB). Using equilibrium constant data, indicate
whether the reaction will proceed as written. (Which side of the reaction is favored?)
phenol + ammonia
O
OH
+ NH3
pKa = 10.0
+ NH4+
pKa = 9.25
The reaction will not proceed, as written, to any significant extent. The reactants are weaker
acids and bases.
ethyl sulfide + acetic acid
O
O
+
+
OH
S
SH
O
pKa = 10.5
pKa = 4.74
The reaction will proceed as written. The products are weaker acids and bases.
8.
Predict the product(s) of the following reactions:
sodium ethoxide
1-iodohexane Æ
+
+
I
O
2-hexene
+
H3O+
Æ
OH
+
+ H3O+
OH
ethanol
+
CH3CH2COOH
Æ
OH
OH
H
+
O
O
NO REACTION!
H
The reactants are much weaker acids and bases.
2-methylcyclopentanol
OH
H2SO4
+
H2SO4 Æ
O
+
O
9.
For the following reduction reactions, predict the product(s), and classify the alcohols as
primary, secondary or tertiary.
OH
LAH
OH
OH
NH
Raney Ni
O
O
NaBH4
OH
H
N
OH
10.
O
Describe a synthetic pathway for the following synthesis. (It is a multi-step problem.)
O
OH
NaBH4
+
H3O
Br
H2SO4
Br2
Br