Which is/are application (s) of adsorption?

Options

A. Humidity can be controlled by adsorption
B. Inert gases cannot be separated by adsorption
C. Softening of hard Water takes place by
adsorption
D. Colouring matter can be removed from the
solution by adsorption

Answer

To determine the applications of adsorption, we will analyze each option provided in the question step by step.

### Step 1: Understanding Adsorption
Adsorption is a surface phenomenon where molecules (adsorbates) adhere to the surface of a solid or liquid (adsorbent). This process is different from absorption, where substances are taken up into the volume of another substance.

### Step 2: Evaluating Each Option

1. **Option 1: Humidity can be controlled by adsorption.**
- **Explanation:** Adsorption is indeed used to control humidity. Substances like silica gel and aluminum gels act as adsorbents to remove moisture from the air. This is a common application in various settings, such as packaging and storage.
- **Conclusion:** This option is correct.

2. **Option 2: Inert gases cannot be separated by adsorption.**
- **Explanation:** This statement is incorrect. In fact, inert gases (noble gases) can be separated through adsorption techniques. For example, mixtures of noble gases can be separated using activated charcoal or coconut charcoal due to their different adsorption capacities at varying temperatures.
- **Conclusion:** This option is incorrect.

3. **Option 3: Softening of hard water takes place by adsorption.**
- **Explanation:** Hard water contains calcium and magnesium ions, which can be removed by passing it through zeolites. Zeolites adsorb these ions and replace them with sodium ions, effectively softening the water.
- **Conclusion:** This option is correct.

4. **Option 4: Colouring matter can be removed from the solution by adsorption.**
- **Explanation:** Adsorption is used to remove colored impurities from solutions. For instance, animal charcoal can adsorb coloring agents, thus purifying the solution.
- **Conclusion:** This option is correct.

### Final Answer
The correct applications of adsorption from the options provided are:
- Option 1: Humidity can be controlled by adsorption.
- Option 3: Softening of hard water takes place by adsorption.
- Option 4: Colouring matter can be removed from the solution by adsorption.

### Summary of Correct Options
- **Correct Options:** 1, 3, and 4.

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