Chapter 5 Surface Chemistry Chemistry class 12 Chapter 5 Surface Chemistry, Class 12 | Page 5

Freundlich Adsorption Isotherm
It gave an empirical relationship between the quantity of gas adsorbed by unit mass of solid adsorbent and pressure at a particular temperature . It can be expressed by the equation .
x / m = kp 1 / n …( i )
Where , x is the mass of the gas adsorbed on mass m of the adsorbent at pressure p , k and n are constants which depend on the nature of the adsorbent and the gas at a particular temperature .
At low pressure , n = 1 , i . e ., x / m = kp At high pressure , n > 1 , i . e ., x / m = k ( independent of p )
Taking logarithm of Eq . ( i )