Download Chem 3.5 #3 Alcohols 1

CHEMISTRY 3.5
Name:
WORKSHEET THREE
1.
2.
ORGANIC CHEMISTRY
Alkenes & Alcohols
Name the following alkenes.
(a)
CH3CHCHCH2CH2CH3
(b)
CH3CH2CHC(CH3)2
Alkenes can be prepared by an ELIMINATION reaction on an alcohol. Complete the following
reaction showing what alkene is produced and write the missing reactant over the arrow.
CH3CH2CH2OH
3.
+ H2O
Alkenes will react with acidified potassium permanganate. In the reaction the alkene molecule is
broken apart at the double bond and the two remnants oxidised up to ketones or carboxylic acids.
The following example is done for you. Name the two products.
H+/MnO4-
CH3CHC(CH3)2
4.
5.
CH3COOH + (CH3)2CO
Name the following alcohols.
(a)
CH3CH2CH2CH2OH
(b)
CH3CHOHCH(CH3)2
Alcohols can be classified as primary, secondary or tertiary. Name and classify the following.
CH3
H
OH
CH3
C
OH
CH3
C
OH
CH3CH2
CH3
CH
CH3
CH3
OH
CH3CH2 CH2 CH2OH
6.
CH3CH2C (CH3)2OH
CH3CH CH2 CH2 CH2 CH3
Alcohols can be prepared from alkenes. Concentrated sulfuric acid diluted to about 50% with
water will effectively add H2O across the double bond. Complete the following equations.
Dil. H2SO4
(a)
CH3CH=CHCH3
(b)
CH2=CHCH3
(c)
In (b), which of the two products is the major one?
Dil. H2SO4
+
7.
8.
9.
(a)
Describe the trend in boiling points in the series methanol, ethanol, propanol, butanol.
(b)
Explain why an alcohol such as propanol has a much higher boiling point than its
corresponding alkane, propane.
(c)
Explain why the lower molecular weight alcohols are soluble in water while the higher
ones are not.
Alcohols undergo some substitution reactions. The most common ones involve replacement of
the OH group with a halogen atom forming haloalkanes. Complete the following equations.
(a)
CH3CH2CH2OH(l) + PCl5 (s) →
(b)
What other Phosphorus compound will produce the same reaction as (a)?
(c)
CH3CH2OH(l) + SOCl2 (l) →
(d)
The by-products of reaction (c) are both gaseous. Explain how is this an advantage.
+ POCl3(l) +
+
+
One of the reagents used to make haloalkanes from alcohols can also be used to distinguish
between primary, secondary and tertiary alcohols. This reagent is a mixture of zinc chloride and
concentrated hydrochloric acid and is called Lucas reagent.
(a)
The zinc chloride acts as a
(b)
Write the equation of the reaction between propan-2-ol and Lucas reagent.
(c)
Describe the order of the reaction rate between Lucas reagent and primary, secondary and
tertiary alcohols.