C12

Question 1

Name the chemical formulas for the Contact processes

Answer 1

S + O2 → SO2
2SO2 + O2 ⇌ 2SO3
H2SO4 + SO3 → H2S2O7
H2S2O7 + H2O → 2H2SO4

Question 2

Use of Sulfur

Answer 2

Manufacture of sulfuric acid

Question 3

Detail stage 1

Answer 3

Oxidation of sulfur
S(s) + O2(g) —> SO2(g) + heat

Question 4

Detail stage 2

Answer 4

Oxidation of sulfur dioxide
2SO2 + O2—-> 2SO3
requirements
- Vanadium(V)oxide (V2O5)
- 2-3 atm (200 kPa)
- 450ºC

exothermic
passed through 4 different beds varying from 400 to 600ºC yield goes from 63% to 99.5%

Question 5

Detail stage 3

Answer 5

SO3(g) + H2SO4(i) —–> H2S2O7(I) (Oleum)
-sulfur trioxide it absorbed into 98% sulfuric acid
-fine mist of H2SO4 could form it not absorbed into water
-difficult to condense and dangerous

Question 6

Detail stage 4

Answer 6

Oleum is added to water to form concentrated sulfuric acid
H2S2O7(I) + H2O(I) —–> 2H2SO4(I)