The Kinetics of the Acid-Catalysed Iodination of Propanone (HL Chemistry Lab VIII)
I. INTRODUCTION
Propanone – also known as acetone – is a colorless, volatile and flammable organic
solvent. It is readily soluble in both water and ethanol. It is a key intermediate in the
manufacture of many polymers.
Image 1.0 – 3D Structure of Propanone (red: oxygen atom, grey: carbon atoms, blue:
hydrogen atoms)
Iodine is a nonmetallic element of the halogen group. It is insoluble in water.
, Image 2.0 – 3D Structure of Iodine (pink: iodine atoms)
Propane reacts with iodine in the present of an acid-catalyst according to the following
equation:
CH COCH + I CH ICOCH + H + I
3 3 2 2 3 + -
The acid-catalyst that will be used is sulfuric acid.
The rate of reaction is defined as the change in concentration of reactants or products per
unit time, measured using the units mol/dm /s, mol/dm /min…etc. Experimentally, it can
3 3
be measured by monitoring a property that will change when the reactants of an
experiment are converted into products, such as a change in pH, change in conductivity,
change in mass or volume, and change in color. The rate of the reaction between iodine
and propanone can be followed by measuring the time taken for the yellow color of iodine
initially present to disappear, as the concentration of iodine decreases as the reaction
proceeds (the reactant is used up in the chemical reaction).
The rate expression is a mathematical expression that expresses the relationship between
the concentration of the reactants and the overall rate of reaction. In the case of this
reaction, the concentrations of propanone, iodine, and also sulfuric acid are surveyed
(sulfuric acid is technically not a reactant, but a catalyst, therefore, its concentration does
I. INTRODUCTION
Propanone – also known as acetone – is a colorless, volatile and flammable organic
solvent. It is readily soluble in both water and ethanol. It is a key intermediate in the
manufacture of many polymers.
Image 1.0 – 3D Structure of Propanone (red: oxygen atom, grey: carbon atoms, blue:
hydrogen atoms)
Iodine is a nonmetallic element of the halogen group. It is insoluble in water.
, Image 2.0 – 3D Structure of Iodine (pink: iodine atoms)
Propane reacts with iodine in the present of an acid-catalyst according to the following
equation:
CH COCH + I CH ICOCH + H + I
3 3 2 2 3 + -
The acid-catalyst that will be used is sulfuric acid.
The rate of reaction is defined as the change in concentration of reactants or products per
unit time, measured using the units mol/dm /s, mol/dm /min…etc. Experimentally, it can
3 3
be measured by monitoring a property that will change when the reactants of an
experiment are converted into products, such as a change in pH, change in conductivity,
change in mass or volume, and change in color. The rate of the reaction between iodine
and propanone can be followed by measuring the time taken for the yellow color of iodine
initially present to disappear, as the concentration of iodine decreases as the reaction
proceeds (the reactant is used up in the chemical reaction).
The rate expression is a mathematical expression that expresses the relationship between
the concentration of the reactants and the overall rate of reaction. In the case of this
reaction, the concentrations of propanone, iodine, and also sulfuric acid are surveyed
(sulfuric acid is technically not a reactant, but a catalyst, therefore, its concentration does
