5.5 Sulphuric Acid

SULPHURIC ACID

By the end of the topic, students should be able to: □ State the uses of sulphur dioxide. □ Describe the manufacture ofsulphuric acid by the Contact Process. □ Describe the acid properties of sulphuric acid. □ State some important uses of sulphuric acid.

Please tick in the box if you can do the above.

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PROPERTIES AND USES OF SULPHUR DIOXIDE  Property 1: -Sulphur dioxide bleaches coloured compounds by removing oxygen from them.  Use based from Property 1: - As a bleaching agent. Used to bleach wood pulp which is important in the manufacture of paper.  Property 2: - Sulphur dioxide is poisonous to all organisms, especially bacteria.  Use based from Property 2: - As a food preservative. In the food industry, sulphur dioxide is added to food in small amounts prevent the growth of moulds and bacteria. MANUFACTURE OF SULPHURIC ACID  Sulphuric acid is one of the most widely used. It is, after all, the cheapest and most readily available strong acid.  Sulphuric acid is manufactured by the Contact Process. This is summarized in the flow chart.

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 The diagram below shows the flow of Contact Process.

PROPERTIES OF DILUTE SULPHURIC ACID 1) Ions in the acid  What are the ions in sulphuric acid? _______________________________________________________ 2) Reaction with metals (Note: Copper and silver do not react with sulphuric acid)  What are the products when metals react with sulphuric acid? _______________________________________________________  Write a balance equation showing a reaction between a metal and sulphuric acid. _______________________________________________________ 3) Reaction with carbonates  What are the products when carbonates react with sulphuric acid?

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_______________________________________________________

 Write a balance equation showing a reaction between a carbonate and sulphuric acid. _______________________________________________________ 4) Reaction with metal oxides and hydroxides (bases)  What are the products when metal oxides or hydroxides react with sulphuric acid? _______________________________________________________  Write a balance equation showing a reaction between a hydroxide and sulphuric acid. _______________________________________________________ 5) Types of salts produced with alkalis  Give an example of an alkali. ___________________  Name two salts that will be form from the given example of alkali that you have given when you react it with sulphuric acid. _______________________________________________________ 6) Effect on indicators  What is the effect of sulphuric acid on litmus paper and Universal Indicator? _______________________________________________________ _______________________________________________________

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USES OF SULPHURIC ACID

1) Manufacture of fertilizers  The most important use of sulphuric acid is in manufacturing fertilizers such as ammonium sulphate, (NH4)2SO4 and superphosphate.  Write down the equation when ammonium sulphate is formed from sulphuric acid and ammonia. _______________________________________________________  Superphosphate is manufactured by reacting the raw material, calcium phosphate Ca3(PO4)2, with concentrated sulphuric acid. The product is called superphosphate because it is a combination of two calcium salts.  Write down the equation when calcium phosphate react with sulphuric acid. _______________________________________________________ 2) Manufacture of detergents  Concentrated sulphuric acid is also used to manufacture detergents. It is used to treat compounds called hydrocarbons to first form an organic acid. Hydrocarbon + concentrated sulphuric acid  organic acid  The organic acid is then neutralized with sodium hydroxide solution to produce the detergent. Organic acid + sodium hydroxide  detergent

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3) As battery acid in cars  Dilute sulphuric acid is used in batteries for cars. Lead plates and lead (IV) oxide plates are also fitted in the batteries.  When sulphuric acid, lead and lead (IV) oxide react, electrical energy is produced. The electrical energy starts the car engine running.

4) Other uses of Sulphuric Acid  Sulphuric acid is also used for making synthetic fibres and for making paints and pigments.  Please proceed to do exercise from: WORKSHEET 1 WORKSHEET 2 WORKSHEET 3

WORKSHEET 1

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WORKSHEET 2

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WORKSHEET 3 9

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