Activity of catalyst :
The ability of a catalyst to increase the rate of a reaction is called activity. For example,
H2+1/2O2→
No reaction.
H2+1/2O2+[Pt]→H2O+[Pt]
(
explosion and very fast reaction takes place )
Selectivity of catalyst :
It is the ability of a catalyst to direct a reaction to yield a particular product. For example, both dehydrogenation and dehydration of ethanol are possible. But in the presence of a suitable catalyst only one reaction is made to occur.
CH3CH2OH
Cu
→
573K
CH3CHO+H2(
dehydrogenation )
CH3CH2OH
Al2O3
→
CH2=CH2+H2O(
dehydration )
