The `R_f` value of A and Bin a mixture determined by TLC in a solvent mixture are 0.65 and 0.42 respectively. If the mixture is separated by column chromatography using the same solvent mixture on a mobile phase, which of the two components A or B will elute first?

Options

A. A will be eluted first
B. B will be eluted first
C. A and B both will be eluted first
D. None

Explanation

To determine which component (A or B) will elute first in column chromatography, we can analyze the given R_f values from the thin-layer chromatography (TLC) results.

### Step-by-Step Solution:

1. **Understanding R_f Values**:
- The R_f value (retention factor) is defined as the distance traveled by the solute divided by the distance traveled by the solvent front.
- For component A, R_f = 0.65, and for component B, R_f = 0.42.

2. **Comparing R_f Values**:
- Since R_f values are given, we can compare them directly. A higher R_f value indicates that the component has moved further up the TLC plate, which typically means it is less strongly adsorbed to the stationary phase.

3. **Interpreting the R_f Values**:
- R_f(A) = 0.65 > R_f(B) = 0.42.
- This indicates that component A has a greater distance moved compared to component B in the same solvent system.

4. **Understanding Elution in Column Chromatography**:
- In column chromatography, the component that is less strongly adsorbed to the stationary phase will elute first. The strength of adsorption is inversely related to the R_f value; a higher R_f value means weaker adsorption.

5. **Conclusion**:
- Since A has a higher R_f value than B, it is less strongly adsorbed and will elute first from the column. Therefore, component A will elute before component B.

### Final Answer:
Component A will elute first in column chromatography.

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