Question

Hydrogen peroxide decomposes to water abd oxygen. The uncatalysed reaction has activation energy of 86 KJ/mol. The activation energy value in the presence of acetanilide is 112 KJ/mol and in the presence of `MnO_(2)` it is 49 KJ/mol . What conclusion can you draw from the above observations ?

Answer 1

The activation energy of a catalysed reaction in presence of `MnO_(2)` catalyst is 49 KJ/mol that is much less than the activation energy of an uncatalysed reaction that is 86 KJ/mol . This show that the rate of decomposition of `H_(2)O_(2)` is increased in the presence of `MnO_(2)` and hence it is a positive catalyst. THe activation energy of the catalysed reaction in the presence of acetanilide is 112 KJ/mol that is such greater than that of an uncatalysed reaction.
This shows that the rate of decomposition of `H_(2)O_(2)` is decreased in the presence of acetanilide and hence it is a negative catalyst.