Although nitrogen does not adsorb on surface at room temperature, it adsorbs on the same surface at `83K` . Which one of the following statements is correct?

Options

A. At 83 K there is formation of Monolayer
B. At 83 K , nitrogen is adsorbed as atoms
C. At 83 K , nitrogen molecules are held by chemical bonds
D. At 83 K, there is formation of multimolecular layers

Answer

To solve the question regarding the adsorption of nitrogen at different temperatures, we need to analyze the behavior of nitrogen molecules on a surface at room temperature and at 83 K.

### Step-by-Step Solution:

1. **Understanding Adsorption**: Adsorption is the process where atoms, ions, or molecules from a gas, liquid, or dissolved solid adhere to a surface. There are two main types of adsorption: physical (physisorption) and chemical (chemisorption).

2. **Behavior at Room Temperature**: The question states that nitrogen does not adsorb on the surface at room temperature. This indicates that the energy of the nitrogen molecules is too high to allow for significant interaction with the surface, preventing adsorption.

3. **Behavior at 83 K**: When the temperature is lowered to 83 K, the kinetic energy of the nitrogen molecules decreases. This lower energy allows nitrogen molecules to overcome the energy barrier for adsorption.

4. **Type of Adsorption**: At 83 K, nitrogen primarily undergoes physical adsorption. This is characterized by weak van der Waals forces, which allow for the formation of layers of adsorbed molecules.

5. **Formation of Layers**: At this temperature, nitrogen can form multi-molecular layers on the surface. This means that multiple layers of nitrogen molecules can be adsorbed, rather than just a single layer (monolayer).

6. **Evaluating the Options**:
- **Option 1**: At 83 K, there is formation of monolayer - **Incorrect**.
- **Option 2**: At 83 K, nitrogen is adsorbed as atoms - **Incorrect**.
- **Option 3**: At 83 K, nitrogen molecules are held by chemical bonds - **Incorrect**.
- **Option 4**: At 83 K, there is formation of multi-molecular layers - **Correct**.

### Conclusion:
The correct statement is that at 83 K, there is formation of multi-molecular layers.