Sulfuric acid and the Contact Process

• What is the contact process?

  Used to produce sulfuric acid
• What kind of reaction does the Contact process involve?

  Reversible
• What are the raw materials needed to make sulfuric acid?

  Sulfur, air and water
• What is stage one of the contact process?

  Sulfur is burned in air to make sulfur dioxide
• Stage 1 of the contact process

  sulfur + oxygen → sulfur dioxide
• What is Stage two of the Contact process?


  Sulfuric dioxide reacts with more oxygen to make sulfur trioxide
• Stage 2 of the contact process

  sulfur dioxide + oxygen ⇌ sulfur trioxide
• What are the conditions needed for stage 2 of the contact process?

  • a catalyst of vanadium oxide
  • Temperature of 450 degrees
  • Pressure of 1-2 atmospheres
• What is stage three of the contact process?

  Sulfuric trioxide reacts with water to make sulfuric acid
• Stage 3 of the contact process

  Water+sulfur trioxide→ sulfuric acid
• Is stage three of the contact process a reversible reaction?

  No
• What happens when sulfur trioxide is added to water directly?

  A high exothermic reaction and leads to the formation of clouds of sulfuric acid
• Is the direct addition of water to sulfur trioxide dangerous?

  Yes
• What is done to minimise the risk of forming clouds of sulfuric acid?


  Adding sulfur trioxide to high concentrated sulfuric acid to form a high corrosive liquid called oleum, to minimise the risk
• What is oleum?


  A highly corrosive substance used to minimise the risk of forming sulfuric acid clouds.
• What is added to oleum to form sulfuric acid again?


  Water
• What is the majority of sulfuric acid used to make?

  Fertilisers
• How is making fertiliser achieved using sulfuric acid?

  By reacting sulfuric acid with ammonia to make ammonium sulfate
• What is the equation for making fertiliser with ammonia and sulfuric acid?

  ammonia + sulfuric acid → ammonium sulfate
• What is the equation for making fertiliser with ammonium hydroxide and sulfuric acid?

  ammonium hydroxide + sulfuric acid → ammonium sulfate + water
• What is sulfuric acid also used in the production of?

  • Detergents
  • Paints
  • Dyes
  • Plastics
  • Artificial fibres
• Where is sulfur rarely found?


  In the ground
• What is sulfur?


  An impurity which is removed from fossil fuels
• Why is sulfur removed from fossil fuels?

  As it causes acid rain when fossil fuels are burned
• as well as a strong acid, what else is sulfuric acid?

  A dehydrating agent
• What is a dehydrating agent?


  A substance that is very good at removing water from other substances
• Concentrated sulfuric acid will remove water molecules from the blue crystals of hydrated copper sulfate and leave behind a white powder, which is anhydrous copper sulfate
• Concentrated sulfuric acid will remove water molecules from glucose molecules to leave behind pure carbon.
• What is the nature of the reaction when water is removed from glucose molecules?

  Highly exothermic and produces lots of steam, forcing the carbon upwards in the reaction
• What forms after the dehydration of glucose molecules?


  Black solid