Question

Statement I : For adsorption $\Delta \text{G},\Delta \text{H},\Delta \text{S}$ all have negative values.

Statement II : Adsorption is an exothermic process in which randomness decreases due to force of attraction between adsorbent and adsorbate.

• A. Statement I is true, Statement II is also true and Statement II is the correct explanation of Statement I.
• B. Statement I is true, Statement II is also true and Statement II is not the correct explanation of Statement I.
• C. Statement I is true, Statement II is false.
• D. Statement I is false, Statement II is true.

Answer 1

Answer: (A)

II is correct explanation of I as adsorption leads to arrangement i.e., decreases randomness $\left(\therefore \Delta \text{S}=-\text{ve}\right)$ at the same time energy is released due to attraction between adsorbate and adsorbent $\left(\therefore \Delta \text{H}=-\text{ve}\right)$ .

Adsorption is a spontaneous process as it occurs on its own. For all spontaneous processes, the change in free energy is negative. Or,

$\therefore \Delta \text{G}=-\text{ve}$