question_answer 40)

    Extent of physisorption of a gas increases with.......... (a) increase in temperature (b) decrease in temperature (c) decrease in surface area of adsorbent (d) decrease in strength of van der Waals' forces

Answer:

                      (b) Extent of physisorption of a gas increases with decrease in temperature. Because in physisorption particles are held to the surface by weak van der Waals' force of attraction hence on increasing temperature they get desorbed easily.