My textbook says that rate of chemisorption decrease with increase in pressure.

textbook image

I do found a similar statement on the web but couldn't understand this.

The rate of chemisorption depends on the flux of chemical species incident on the substrate surface. High incident flux results in high chemisorption rate. As we keep on increase the pressure the incident flux gets reduced due to low diffusion length of species and hence a decrease in the rate of chemisorption. Low pressures result in larger diffusion length of chemical species towards the substrate. As a result the flux incident on substrate surface increases which eventually results in high chemisorption rate.

Source- https://www.quora.com/Why-does-chemisorption-decrease-with-an-increase-in-pressure

Any explanation for this Statement would be highly appreciated.


And it does favour it.

Decreasing of rate of chemisorption is not decreasing of chemisorption.

Decreasing of this rate is another instance of application of the principle. A system approaching saturation reacts by a way of decreasing the rate this saturation is approached.

  • $\begingroup$ Can you please elaborate the last line of your answer $\endgroup$
    – Govind
    Jan 30 at 18:52
  • $\begingroup$ I understood the thermodynamics part, that the equilibrium would shift in forward direction in accordance to the principle $\endgroup$
    – Govind
    Jan 30 at 19:15
  • $\begingroup$ But can you explain how the rate is decreasing, since the pressure is increasing so number of molecules striking the surface should increase and hence the rate should also increase $\endgroup$
    – Govind
    Jan 30 at 19:16
  • $\begingroup$ There is possible confusion, if you / your textbook mean kinetic rate like dn/dA/dt, or chemisorption curve rate dn/dA/dp. A context could help. $\endgroup$
    – Poutnik
    Jan 30 at 21:32
  • $\begingroup$ Yes , I do think that the statement itself is not clear. $\endgroup$
    – Govind
    Jan 31 at 6:32

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