Question

Explain any one factor affecting the rate of chemical reaction.

Answer 1

Catalyst: The substance in whose presence the rate of a chemical reaction increases without causing any chemical change to it is called a catalyst.

On heating, potassium chlorate \[\ce{(KClO3)}\] decomposes slowly.

\[\ce{2KClO3 ->[\Delta] 2KCl + 3O2}\]  .....

The rate of the above reaction neither increases by reducing the particle size nor by increasing the reaction temperature. However, \[\ce{KClO3}\] decomposes rapidly in the presence of manganese dioxide \[\ce{(MnO2)}\] to liberate \[\ce{O2}\] gas. No chemical change takes place in \[\ce{MnO2}\] in this reaction.

The decomposition of hydrogen peroxide into water and oxygen takes place slowly at room temperature. However, the same reaction occurs at a faster rate when adding manganese dioxide \[\ce{(MnO2)}\] powder to it.