The document describes the contact process for producing sulfuric acid from sulfur. It involves burning sulfur to produce sulfur dioxide, then converting the sulfur dioxide to sulfur trioxide in a converter using a catalyst and air. The sulfur trioxide is then absorbed in concentrated sulfuric acid in an absorption tower to produce more sulfuric acid.

1.  Lead Chamber Process
 Produces relatively dilute acid (62%–78% H2SO4)
 Contact Process

2.  Iron pyrite (FeS2)
(Silicon free FeS2 contain about 53.4% S)
 Elemental sulfur
 Air

3.  Melting and burning of sulfur
 Drying off air
 Recovery of heat form SO2
 Conversion of SO2 to SO3 a convertor
 Absorption of SO3 in sulfuric acid

4. Combustion
Chamber
(combustion of
sulfur)
-->
Converter
(conversion of
sulfur dioxide)
-->
Absorption
Tower
(sulfur trioxide
absorbed
into the sulfuric
acid mist
-->
Hydration of
Oleum
to produce
sulfuric acid

8. S(s) + O2(g) → SO2(g)
2SO2(g) + O2(g) → 2SO3(g)
SO3(g) + H2SO4 → H2S2O7
H2S2O7(l) + H2O(l) → 2H2SO4(l)

9. 1. Equilibrium is an inverse function of
temp. and direct function of oxygen
to sulfur dioxide ration
2. Rate of reaction is direct function of
temp.
3. Removal of sulfur trioxide formed
allow more sulfur dioxide to be
converted

11. Prepare a flow chart to show the sequence of
processes used to convert sulfur into
concentrated sulfuric acid. Write equations
for significant chemical reactions beside the
appropriate section of the flow chart.

12. ◦ Construct a table that lists the main by-products
of sulfuric acid production from sulfur dioxide
and describes how these problems are treated or
reduced.

13.  During the contact process, the temperature
of the gas increases as it passes through each
catalyst bed in the converter. The gas must
be diverted for cooling before returning for
another pass.
 a Why does the temperature of the gas rise?
 b Why is it necessary to cool the gas?
 c What side-benefit is obtained from the need
to cool the gas?

14.  Although water reacts directly with sulfur
trioxide to form sulfuric acid, this reaction is
not employed when sulfuric acid is made.
 A Explain why not.
 B Describe the process that is used.
 c Write equations for the reactions that
occur in the process described in part b
above.

15.  Air is thoroughly purified before it is used in
the contact process. Explain the reason for
this

16. Sulfur dioxide is present in emissions from
sulfuric acid plants.
 a Why is the release of large amounts of
sulfur dioxide in the atmosphere
 undesirable?
b What is done to limit the extent of these
emissions in sulfuric acid plants?

17.  Under the title ‘Sulfuric acid: the world’s most
wanted chemical’, write a paragraph that uses
the words: fertilizers, contact process,
smelting, converter, absorption tower,
equilibrium, reaction rate and catalytic
oxidation.

18. Describe two ways that expenses are
minimized in the contact process.

19. Construct a concept map that includes the
following terms: sulfuric acid, fertilizers,
oxidation, contact process, converter,
absorption tower, oxidation, reaction rate,
equilibrium yield and catalyst

20. In the commercial production of sulfuric acid,
sulfur dioxide is oxidized to sulfur trioxide by
oxygen gas.
a) Write a balanced chemical equation for the
reaction.
b) Write an expression for the equilibrium
constant for the reaction.
c) Predict the reaction conditions that would favor
maximum equilibrium yield of sulfur trioxide.
Explain your reasoning.
d) How would these conditions affect the rate of
reaction?
e) Discuss the conflict that arises in the choice of
reaction conditions for the contact process and
the strategies used to deal with this conflict.

21.  Your firm has asked you to design a new sulfuric
acid plant, briefly list important factors that you
would consider when deciding:
a) whether to use powdered sulfur from a local
supplier or molten sulfur transported a greater
distance
b) if sulfur were to be burnt in air or oxygen
c) whether to obtain sulfur dioxide by burning
sulfur or from the waste gases of a copper
smelter
d) whether to use air or oxygen for the reaction in
the converter.

22. Oleum
Term used to describe fuming sulfuric acids
and consists of SO3 dissolved in 100% H2SO4.
As it contains various compositions of SO3 in
H2SO4, therefore found in various strengths.
It is normally turbid and off-white in
appearance

23. %age oleum
The percentage of SO3 in the oleum is regarded
as percentage oleum
Thus, for example, 20% oleum contains 20%
SO3 and 80% H2SO4 by weight