Question

Plate A, below, represents the TLC chromatogram of a compound run in hexanes. The same compound was

then spotted on a large TLC plate and again run in hexanes. Which TLC plate, B, C, or D, correctly represents

how far the compound would run on the longer plate?
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Answer 1

Answer:

The same compound was then spotted on a large TLC plate and again run in hexanes. Which TLC plate, B, C, or D, correctly represents how ...

Answer 2

TLC plate showing the correct representation with the given plate

Explanation:

Plate C correctly represents the TLC chromatogram of plate A.

The ratio of distance travelled by the center of spot to the solvent front is called retardation factor. It is represented by $R_{f}$.

In plate A, approximate length of plate is 7 units.

Distance of solvent front is 5.5 units.

Distance solute travelled is 3.5 units.

so the retardation factor for the solute in hexane solvent would be:

$R_{f} = \frac{3.5}{5.5} = 0.63$

In plate C, approximate length of plate is 9 units.

Distance of solvent front is 7.5 units.

Distance solute travelled is nearly 4.8 units.

Retardation factor for sample in hexane solvent in plate C would be:

$R_{f} = \frac{4.8}{7.5} = 0.64$

Rf values for plate C and plate A are very close to each other.

Rf value of any solute remains fixed in a particular solvent. Here in plate A, B, C and D, we are not changing the solvent system, so the ratio of distance between solute and solvent will be constant.