Question

Which is correct in case of Van der Waals adsorption?

• A. High temperature, low pressure
• B. High temperature, high pressure
• C. Low temperature, low pressure
• D. Low temperature, high pressure

Answer 1

Answer: (D)

Low temperature, high pressure

• If the accumulation of gas on the surface of a solid occurs on account of weak van der Waals’ forces, the adsorption is termed as physical adsorption or physisorption.
  

Hence, Physisorption can also be called as Van der Waals adsorption.

• Physical adsorption of a gas by a solid is generally reversible. We can say by Le-Chatelier's principle that more of gas is adsorbed when pressure is increased as the volume of the gas decreases and since the adsorption process is exothermic, the physical adsorption occurs readily at low temperature and decreases with increasing temperature.
  
• So the correct case is when it is Low temperature and high pressure the Physisorption tends to happen.