Contact process

IGCSE CHEMISTRY
Haber and Contact Process

The Contact Process

Sulphuric Acid H2SO4

The Contact Process

Sulphuric Acid H2SO4

Raw materials: sulphur,

oxygen, water

Multiple Choice

The Contact process is used for the manufacture of...

• Sulfur

• Sulfur dioxide

• Sulfur trioxide

• Sulfuric acid

Multiple Select

Select all the raw materials for the Contact process.

• Sulfur

• Air

• Hydrogen

• Water

The Contact Process

Sulphuric Acid H2SO4

Raw materials: sulphur,

oxygen, water

Conditions:

Catalyst (vanadium oxide)
Pressure of 2 atmospheres
Temperature of about 450oC

Multiple Choice

What are the conditions used in the Contact process?

• $$1\ atm$$ and $$450\ \degree C$$

• $$200\ atm$$ and $$450\ \degree C$$

• $$450\ atm$$ and $$1\ \degree C$$

• $$450\ atm$$ and $$200\ \degree C$$

Multiple Choice

Name the catalyst used in the Contact process.

• Finely-divided Iron

• Vanadium (V) Oxide

• Nickel

• Chromium

The Contact Process

Three stage process.

The Contact Process

Three stage process.

1.

Preparation of sulphur dioxide

S(s) + O2(g) 🡪 SO2(g)

The Contact Process

Three stage process.

1.

Preparation of sulphur dioxide

S(s) + O2(g) 🡪 SO2(g)

2. Preparation of sulphur oxide

2SO(s) + O2(g) 2SO3(g)

Multiple Choice

In the Contact process, what happens to the equilibrium when the pressure is increased?

• Shifts to the left

• Shifts to the right

• No change in equilibrium

The Contact Process

Three stage process.

1.

Preparation of sulphur dioxide

S(s) + O2(g) 🡪 SO2(g)

2. Preparation of sulphur oxide

2SO(s) + O2(g) 2SO3(g)

3. Preparation of sulphuric acid

SO3(s) + H2O (l) 🡪 H2SO4(l)

Sulfur tri oxide SO₃ cannot be added directly to the water as it is highly exothermic and corrosive in nature. It produces fog of sulfuric acid gases and highly dangerous. Sulfur tri oxide SO₃ first dissovedin conc. sulfuric acid to form oleum and then diluted to produce sulfuric acid.

​

Sulfur trioxide cannot be added directly to the water

Multiple Choice

Why is sulfur trioxide not dissolved directly in water?

• There would be no reaction

• Sulfur trioxide is insoluble in water

• Sulfur trioxide reacts violently with water to produce fog of H₂SO₄

• Sulfur trioxide needs to be dry

Multiple Choice

What is H₂S₂O₇?

• Concentrated sulfuric acid

• Sulfur trioxide

• Oleum

• Hydrogen sulfate

The Contact Process

Three stage process.

1.

Preparation of sulphur dioxide

S(s) + O2(g) 🡪 SO2(g)

2. Preparation of sulphur oxide

2 stages: (a) the
sulphur oxide is
dissolved in conc
sulphuric acid to
produce oleum

(b) The oleum is
then diluted to
give conc sulphuric
acid which is 98%
acid and 2% water

Uses of sulphuric acid

https://youtu.be/mym1rRPX6F4

Multiple Select

What are the uses of sulfuric acid? Choose the correct answers.

• In the manufacture of detergents and fertilisers

• As a battery acid

• As food preservative

• As a bleach

​Recap

Multiple Choice

The enthalpy change of a reaction in the Contact process reads as $$\Delta H=-197$$  kJ/mol. What does this tell us about the reaction?

• It is an exothermic reaction

• It is an endothermic reaction

• It loses 197 grams of reactant

• It produces 197 grams of product

Multiple Choice

What is the pH of sulfuric acid?

• pH 2

• pH 7

• pH 8

• pH 13