JEE Main & Advanced Chemistry Surface & Nuclear Chemistry / भूतल और नाभिकीय रसायन Activity And Selectivity  

(1) Activity : Activity is the ability of catalysts to accelerate chemical reaction, the degree of acceleration can be as high as \[{{10}^{10}}\] times in certain reactions. For example reaction between \[{{H}_{2}}\]and \[{{O}_{2}}\] to form \[{{H}_{2}}O\]in presence of platinum as catalyst takes place with explosive violence.

In absence of catalyst, \[{{H}_{2}}\]and \[{{O}_{2}}\]can be stored indefinitely without any reaction.    

(2) Selectivity : Is the ability of catalysts to direct reaction to yield particular products (excluding other). Example :    

(i) \[n-\text{heptane}\xrightarrow{Pt}\]                              

(ii) \[C{{H}_{3}}CH=C{{H}_{2}}\xrightarrow{BiMo{{O}_{4}}}C{{H}_{2}}=\overset{\,\,\,O}{\mathop{\overset{\,\,\,\,||}{\mathop{\underset{\text{Acrolein}}{\mathop{CHCH}}\,}}\,}}\,\]