Sulfuric Acid is[1]

Sulfuric Acid

H2SO4

• commercially important raw material

Sulfuric Acid

H2SO4

• commercially important raw material

• more sulfuric acid made than any other compound

Sulfuric Acid

H2SO4

• commercially important raw material

• more sulfuric acid made than any other compound

• fertilisers, paints and pigments, detergents, car batteries, laboratory acid

Sulfuric Acid

H2SO4

• manufacturemanufacture

• propertiesproperties

• usesuses

Sulfuric Acid

H2SO4

• manufacturemanufacture

• propertiesproperties

• usesuses

H2O Air Sulfur

Sulfuric Acid

H2SO4

• manufacturemanufacture

H2O Air Sulfur

Step 1: Formation of SO2

either S + O2 SO2

or 2ZnS + 3O2 2SO2 + 2ZnO

Sulfuric Acid

H2SO4

• manufacturemanufacture

H2O Air Sulfur

Step 2: Formation of SO3 the Contact Process

2SO2 + O2 2SO3

exothermic

Sulfuric Acid

H2SO4

• manufacturemanufacture

H2O Air Sulfur

Step 3: Formation of Oleum

SO3 + H2SO4 H2S2O7

{the direct combination of SO3 with water is too exothermic and forms a fine mist of acid}

Sulfuric Acid

H2SO4

• manufacturemanufacture

H2O Air Sulfur

Step 4: Dilution of Oleum

H2O + H2S2O7 2H2SO4

the oleum is diluted to give the desired concentration of sulphuric acid

Sulfuric Acid

H2SO4

• manufacturemanufacture

H2O Air Sulfur

Step 2: Formation of SO3 the Contact Process

2SO2 + O2 2SO3

exothermicLet’s look at this equilibrium more closely….

Sulfuric Acid

Step 2: Formation of SO3 the Contact Process

2SO2 + O2 2SO3

exothermic

Factors:• CatalystCatalyst

• TemperatureTemperature

• PressurePressure

Sulfuric Acid

Step 2: Formation of SO3 the Contact Process

2SO2 + O2 2SO3

exothermic

Factors:• Catalyst Catalyst VV22OO55

• TemperatureTemperature

• PressurePressure

Sulfuric Acid

Step 2: Formation of SO3 the Contact Process

2SO2 + O2 2SO3

exothermic

Factors:• Catalyst Catalyst VV22OO55

• Temperature Temperature 450450ooCC

• PressurePressure

Sulfuric Acid

Step 2: Formation of SO3 the Contact Process

2SO2 + O2 2SO3

exothermic

Factors:• Catalyst Catalyst VV22OO55

• Temperature Temperature 450450ooCC

• Pressure Pressure 1-2 atmospheres1-2 atmospheres

Sulfuric Acid

Step 2: Formation of SO3 the Contact Process

2SO2 + O2 2SO3

exothermic

Factors:• Catalyst Catalyst VV22OO55

•Speeds up time taken to achieve equilibrium• Several catalyst beds used to achieve high yield

Sulfuric Acid

Step 2: Formation of SO3 the Contact Process

2SO2 + O2 2SO3

exothermic

Factors:• Temperature Temperature 450450ooCC

• The yield of SO3 increases as T is decreased

Sulfuric Acid

Step 2: Formation of SO3 the Contact Process

2SO2 + O2 2SO3

exothermic

Factors:• Pressure Pressure 1-2 atmospheres1-2 atmospheres

• The yield of SO3 increases as P is increased

30New Way Chemistry for Hong Kong A-Level Book 430

44.4 Sulphuric(VI) Acid (SB p.136)

A flow diagram f or the Contact process

Sulfuric Acid

H2SO4

• manufacturemanufacture

• propertiesproperties

• usesuses

Sulfuric Acid

H2SO4

• manufacturemanufacture

• propertiesproperties

• usesuses

Dehydrating agent

Viscous liquid

Sulfuric Acid

H2SO4

• manufacturemanufacture

• propertiesproperties

• usesuses

Dehydrating agent

Viscous liquidViscous liquid

Conc H2SO4 will dehydrate hydrated copper sulphateand carbohydrates