Which one of the following characteristics is not correct for physical adsorption?

Options

A. Adsorption on solids is reversible
B. Adsorption increases with increase in temperature
C. Adsorption is spontaneous
D. Both enthalpy and entropy of adsorption are negative

Explanation

To determine which characteristic is not correct for physical adsorption, we can analyze the properties of physical adsorption step by step.

### Step 1: Understanding Physical Adsorption
Physical adsorption, also known as physisorption, is characterized by weak van der Waals forces between the adsorbate (the molecules being adsorbed) and the adsorbent (the surface on which adsorption occurs).

### Step 2: Characteristics of Physical Adsorption
1. **Reversibility**: Physical adsorption is generally reversible. The weak forces allow the adsorbate to detach easily from the adsorbent.
2. **Effect of Temperature**: As temperature increases, physical adsorption decreases. Higher temperatures provide energy that can overcome the weak forces of attraction, leading to desorption.
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