Worksheet 3.1

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Ozone and its chemical properties

T 1

Draw the second resonance structure of the ozone molecule below.


T 2

Explain why the O3 molecule has dipole character and compare it with a CO2 molecule and a H2O molecule.

T 3

If ozone reacts with an alkene (ozonolysis), the alkene molecule is cracked at the C=C double bond. The products of the reaction are two carbonyl compounds.  Write down and name the products of the ozonolysis of:

a) 2-butene

b) 2-methyl-2-butene

Some properties of ozone:

l T boiling = -112.5° C

l poorly water-soluble

l T melting = -251.4° C

l soluble in organic solvents i.e. in CF2Cl2

l µ = 0.49 D

l toxic

l bluish color

l O2/O3 (w (O3) < 10% stable below 100° C

l characteristic smell

l O3(l), O3(s) explode during contact

strong oxidizing agent:

examples of oxidation reactions with ozone:

T 4

Can oxidation by ozone proceed better at high or low pH? Give reasons for your answer using the information in the box above.

T 5

Iodide ions can also be oxidized by molecular chlorine. Write down the reaction scheme and explain the difference to reaction 1 in the box above.


In atmospheric cloud droplets, ozone oxidises sulphurous acid (sulphur dioxide in water). This oxidation is most efficient at high pH levels.

  • Discuss this result.
  • Refer to your results from T4.



Worksheet, Solution

About this page:
authors: M. Seesing, M. Tausch - Universität Duisburg-Essen, Duisburg, Germany
scientific reviewer: Dr. Rolf Sander - Max Planck Institute for Chemistry, Mainz - 2004-05-18
last update: 2004-06-07
Last modified: Thursday, 4 April 2019, 2:37 PM