Fill in the blanks 

1. The surface of separation of the two phases where the concentration of adsorbed molecule is high is known as ……

2. In adsorption, if the concentration of a substance in the interface is high, it is called ………

3. The process of removing a adsorbed substance from the surface is called ……

4. Adsorption is always accompanied by decrease in ……

5. A term …… is used for sorption of gases on metal surfaces

6. M.C. Bain introduced a term …… to represent the simultaneous adsorption and absorption. 

7. In chemical adsorption, gas molecules are held to the surface by formation of chemical bond and nearly ……… is given out as heat of adsorption 

8. In physical adsorption …… exist between adsorbent and adsorbate 

9. Heat of adsorption is low hence physical adsorption occurs at …….

10. ……… involves the formation of activated complex with appreciable activation energy.

Difference between Echo and Reverberation.