In a box a mixture containing `H_2, O_2` and CO along with charcoal is present then variation of pressure with the time will be as follows

Options

A.
B.
C.
D.

Answer

To solve the problem of how the pressure of a mixture containing \( H_2, O_2, \) and \( CO \) along with charcoal varies with time, we can follow these steps:

### Step 1: Understand the Components
We have a mixture of gases: hydrogen (\( H_2 \)), oxygen (\( O_2 \)), and carbon monoxide (\( CO \)), along with charcoal. Charcoal acts as an adsorbent.

**Hint:** Identify the role of each component in the mixture.

### Step 2: Initial Pressure
Initially, the pressure in the box is high due to the presence of these gases. The pressure is a result of the number of gas molecules present in the box.

**Hint:** Consider how gas pressure is related to the number of gas molecules.

### Step 3: Adsorption Process
As time passes, the gas molecules begin to adsorb onto the surface of the charcoal. This is a surface phenomenon where gas molecules stick to the surface of the charcoal, reducing the number of free gas molecules in the box.

**Hint:** Recall that adsorption reduces the number of gas molecules available to exert pressure.

### Step 4: Pressure Decrease
As adsorption occurs, the pressure in the box decreases because fewer gas molecules are available to contribute to the pressure. This decrease in pressure will continue until the adsorption sites on the charcoal are filled.

**Hint:** Think about how the filling of adsorption sites affects the pressure.

### Step 5: Equilibrium Point
Once all the available adsorption sites on the charcoal are occupied, the pressure will stabilize and become constant. This is because no more gas molecules can adsorb onto the charcoal, and the pressure will not change significantly over time.

**Hint:** Identify the point at which the adsorption sites are fully occupied.

### Step 6: Graph Interpretation
The graph of pressure versus time will show a decrease in pressure over time, followed by a plateau where the pressure remains constant. This indicates that the adsorption process is complete.

**Hint:** Visualize how the graph would look based on the described behavior of pressure over time.

### Conclusion
Thus, the variation of pressure with time will show a decreasing trend that eventually levels off, indicating that the adsorption process has reached completion.

**Final Answer:** The correct option is **C**, which shows that pressure decreases non-linearly and then becomes constant.

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