In the observation of a chemisorption isobar, the extent of adsorption () eventually drops rapidly a — Surface Chemistry Chemistry Question
Question
In the observation of a chemisorption isobar, the extent of adsorption ($x/m$) eventually drops rapidly at exceedingly high temperatures after passing its maximum. What is the precise reason for this decline?
💡 Solution & Explanation
The initial increase in chemisorption is due to the gas acquiring the necessary activation energy to form chemical bonds. However, at exceedingly high temperatures, the intense thermal kinetic energy of the system exceeds the bond dissociation energy. The chemical bonds holding the adsorbate to the surface rupture, drastically increasing the rate of desorption and causing $x/m$ to fall.