Autocatalysis

Question 1

What is autocatalysis

Answer 1

When one of the products of the reaction can catalyse the reaction by bringing about an alternative reaction route with lower activation energy

Question 2

How does Mn2+ act as auto catalyst

Answer 2

Oxidised by MnO4- to form Mn3+ which is then reduced to Mn2+ and oxidises C2O4 2- rather than the MnO4- oxidising it itself

Question 3

Equations for Mn2+ (MnO4-) acting as auto catalyst with C2O42-

Answer 3

Overall: 2MnO4 - + 16H+ + 5C2O4 2- ——> 2Mn2+ + 8H2O + 10CO2

Intermediate reactions:
4Mn2+ + MnO4- + 8H+ —-> 5Mn3+ + 4H2O
2Mn3+ + C2O4 2- —-> 2CO2 + 2Mn2+

Question 4

What is required for reaction between MnO4- and C2O4 2- in acidic conditions

Answer 4

A small amount of initial heating in order to produce some Mn2+ for autocatalysis

Question 5

What happens when transition metal acts as autocatalyst

Answer 5

Transition metal ion forms an intermediate, then further reaction occurs to regenerate original transition metal ion