Transition Metals - Catalysts

Question 1

Contact Process - Using V2O5 as a catalyst

Answer 1

V2O5 + SO2 → V2O4 + SO3

V2O4 + 1/2 O2 → V2O5

Overall: SO2 + 1/2 O2 → SO3

Question 2

Reaction between S2O8 2- and I- using Fe 2+ as a catalyst

Answer 2

Overall: S2O8 2- + 2 I- → 2 SO4 2- + I2

Mechanism:
2 Fe 2+ + S2O8 2- → 2 Fe 3+ + 2 SO4 2-

2 Fe 3+ + 2 I- → 2 Fe 2+ + I2

Intermediate = Fe 3+

Question 3

Reaction between MnO4- and C2O4 2-

Answer 3

2 MnO4 - + 5 C2O4 2- + 16 H+ → 2 Mn 2+ + 8 H2O + 10 CO2

Autocatalyst = Mn 2+

Question 4

Mechanism for reaction of MnO4- and C2O4 2- using Mn 2+ as an autocatalyst

Answer 4

1. 2 MnO4 - + 5 C2O4 2- + 16 H+ → 2 Mn 2+ + 8 H2O + 10 CO2
2. 4 Mn 2+ + MnO4- + 8H+ → 5 Mn 3+ + 4 H2O
3. 2Mn 3+ + C2O4 2- → 2 Mn 2+ + 2 CO2

Intermediate = Mn 3+