go to the AUS-e-TUTE homepage
home test Join AUS-e-TUTE game contact
 

 

Hydration of Alkenes

Key Concepts

  • Hydration of alkenes is an addition reaction.

  • Water adds across the alkene's double bond.

  • This addition follows Markovnikov's rule.
        (the H+ of H2O goes to the C atom that has the greatest number of H atoms)

  • General Equations:
    word equation: alkene + water H+
    alkanol
    chemical equation:
         
    R-C=C-R'
     |
    H
     |
    H
     
    + H-O-H H+
     H
    |
     O
    |
    -H
     
    R-C-C-R'
     |
    H
     |
    H
     

    H+ represents a dilute, strong acid such as dilute sulfuric acid.
    R and R' represent hydrogen (H) or alkyl groups (alkane chains).

YouTube Animation

Example: Hydration of ethene (ethylene)

In the presence of a dilute strong acid, water will add across the double bond in ethene (ethylene) to produce ethanol (ethyl alcohol).

ethene
(ethylene)
+ water H+
ethanol
(ethyl alcohol)
C2H4 + H2O H+
C2H5OH
CH2=CH2 + H2O H+
CH3-CH2OH
         
H- C = C -H
  |
H
  |
H
 
+ H-O-H H+
  H
|
  O
|
-H
 
H- C - C -H
  |
H
  |
H
 

Example: Hydration of propene (propylene)

In the presence of a dilute strong acid, water will add across the double bond in propene (propylene).

There are two possible products resulting from the addition of water to propene, propan-1-ol (1-propanol) and propan-2-ol (2-propanol).

Markovnikov's Rule predicts that propan-2-ol (2-propanol) will be the major product, while the other structural isomer, propan-1-ol (1-propanol), will be only a minor product of the reaction.

propene
(propylene)
+ water H+
propan-2-ol
(major product)
+ propan-1-ol
(minor product)
CH2=CH-CH3 + H2O H+
CH3-CH(OH)-CH3
(major product)
+ CH3-CH2-CH2OH
(minor product)
          H
|
 
H- C = C - C -H
  |
H
  |
H
  |
H
 
+ H-O-H H+
  H
|
  OH
|
  H
|
 
H- C - C - C -H
  |
H
  |
H
  |
H
 
+
  OH
|
  H
|
  H
|
 
H- C - C - C -H
  |
H
  |
H
  |
H
 


What would you like to do now?
advertise on the AUS-e-TUTE website and newsletters
 
 

Search this Site

You can search this site using a key term or a concept to find tutorials, tests, exams and learning activities (games).
 

Become an AUS-e-TUTE Member

 

AUS-e-TUTE's Blog

 

Subscribe to our Free Newsletter

Email email us to
subscribe to AUS-e-TUTE's free quarterly newsletter, AUS-e-NEWS.

AUS-e-NEWS quarterly newsletter

AUS-e-NEWS is emailed out in
December, March, June, and September.

 

Ask Chris, the Chemist, a Question

The quickest way to find the definition of a term is to ask Chris, the AUS-e-TUTE Chemist.

Chris can also send you to the relevant
AUS-e-TUTE tutorial topic page.

 
 
 

Share this Page

Bookmark and Share
 
 

© AUS-e-TUTE