For Adsorption phenomenon,

Options

A. `DeltaH = +ve,DeltaS = -ve`
B. `DeltaH= -ve, DeltaS = +ve`
C. `DeltaH= -ve, DeltaS = -ve`
D. `DeltaH= +ve, DeltaS = +ve`

Explanation

To solve the question regarding the conditions for the adsorption phenomenon, we will analyze the thermodynamic parameters involved in the process. Here’s a step-by-step solution:

### Step 1: Understand the Adsorption Process
Adsorption is the process where molecules from a gas or liquid adhere to a solid surface. This process can be either physical (physisorption) or chemical (chemisorption).

### Step 2: Analyze the Change in Entropy (ΔS)
During adsorption, the molecules that are adsorbed lose some degree of freedom and randomness. This leads to a decrease in entropy (ΔS). Therefore, we can conclude:
- **ΔS < 0** (Entropy decreases)

### Step 3: Analyze the Change in Enthalpy (ΔH)
Adsorption is generally an exothermic process, meaning it releases heat. For a process to be spontaneous, the change in Gibbs free energy (ΔG) must be negative. The relationship between ΔG, ΔH, and ΔS is given by the equation:
\[ ΔG = ΔH - TΔS \]
For the process to be spontaneous:
- **ΔG < 0**

### Step 4: Apply the Gibbs Free Energy Equation
Since we know that ΔS is negative (ΔS < 0), the term -TΔS will be positive. To ensure that ΔG remains negative, ΔH must also be negative:
- **ΔH < 0** (Enthalpy decreases)

### Step 5: Conclusion
For the adsorption phenomenon to occur spontaneously, both conditions must be satisfied:
1. **ΔS < 0** (Entropy decreases)
2. **ΔH < 0** (Enthalpy decreases)

Thus, the correct conditions for adsorption are:
- **ΔS < 0 and ΔH < 0**.