During a paper chromatography analysis of a mixture of amino acids, the solvent front trav… — JAMB UTME

During a paper chromatography analysis of a mixture of amino acids, the solvent front travels a distance of $16.0\text{ cm}$ from the baseline. A spot corresponding to a particular amino acid is observed to travel a distance of $6.4\text{ cm}$ from the baseline. What is the retardation factor ( $R_f$ ) of this amino acid?

$0.40$ Answer
B
$2.50$
C
$0.67$
D
$9.60$

Answer

The retardation factor (

R_f

) of the amino acid is

0.40

The retardation factor (

R_f

) is determined by dividing the distance moved by the solute spot (

6.4\text{ cm}

) by the distance moved by the solvent front (

16.0\text{ cm}

), giving

\frac{6.4}{16.0} = 0.40

Step-by-Step Solution

Identify the formula for the retardation factor (

R_f

)

R_f = \frac{\text{Distance travelled by solute spot}}{\text{Distance travelled by solvent front}}

By definition in paper chromatography,

R_f

is the ratio of solute displacement to solvent displacement relative to the origin line.

Substitute the given values into the equation

R_f = \frac{6.4\text{ cm}}{16.0\text{ cm}}

The solute displacement is

6.4\text{ cm}

and the solvent front displacement is

16.0\text{ cm}

Calculate the dimensionless

R_f

value

R_f = 0.40

Performing the division gives

0.40

, which is less than

1.0

as required for valid

R_f

values.

Key Concept

Calculation of Retardation Factor (Rf) in Paper Chromatography

Estimated Time:1m 0s

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