Which of the following statements is not true about partition chromatography?

Options

A. Stationary phase is a finely divided solid adsorbent
B. Separation depends upon equilibration of solute between a mobile and a stationary phase
C. Paper chromatography is an example of partition chromatography
D. Mobile phase can be a gas

Answer

To determine which statement is not true about partition chromatography, let's analyze each option step by step.

### Step 1: Understanding Partition Chromatography
Partition chromatography is a technique used to separate components of a mixture based on their distribution between a stationary phase and a mobile phase. The stationary phase is typically a liquid that is coated on a solid support, while the mobile phase can be a liquid or gas.

### Step 2: Analyzing Each Statement
1. **Statement A**: "The stationary phase is a finely divided solid adsorbent."
- This statement is **not true** for partition chromatography. In partition chromatography, the stationary phase is usually a liquid that is coated on a solid support, not a finely divided solid adsorbent.

2. **Statement B**: "Separation depends upon equilibration of solute between a mobile and stationary phase."
- This statement is **true**. The separation in partition chromatography is based on the equilibrium distribution of solutes between the two phases.

3. **Statement C**: "Paper chromatography is an example of partition chromatography."
- This statement is **true**. Paper chromatography is indeed a type of partition chromatography where the stationary phase is water held in the fibers of the paper.

4. **Statement D**: "The mobile phase can be a gas."
- This statement is **not true** for partition chromatography. The mobile phase is typically a liquid in partition chromatography, although gas chromatography is a different technique.

### Step 3: Conclusion
Based on the analysis:
- The statements that are **not true** about partition chromatography are A and D. However, since the question asks for one statement that is not true, we can conclude that **Statement D** is the most directly incorrect in the context of partition chromatography.

### Final Answer
The statement that is not true about partition chromatography is: **D. The mobile phase can be a gas.**

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