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A paper chromatograph of four dyes, G, P, R and Y, is shown below - VCE - SSCE Chemistry - Question 4 - 2016 - Paper 1

Question 4

A paper chromatograph of four dyes, G, P, R and Y, is shown below. A. solvent front B. origin The Rf value of the dye most strongly adsorbed onto the stationary p... show full transcript

Worked Solution & Example Answer:A paper chromatograph of four dyes, G, P, R and Y, is shown below - VCE - SSCE Chemistry - Question 4 - 2016 - Paper 1

Step 1

Identify the dye adsorbed the most

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Answer

To determine which dye is most strongly adsorbed onto the stationary phase, we look for the dye that has the lowest Rf value. The Rf value is calculated as:

$Rf = \frac{distance\ moved\ by\ the\ dye}{distance\ moved\ by\ the\ solvent\ front}$ .

From the chromatograph, measure the distance the solvent front has moved, which appears to be approximately 18 cm. We can then measure the distance each dye has moved from the origin. Based on visual analysis, the dye G appears to have moved approximately 5.5 cm.

Calculating the Rf value for dye G:

$Rf_G = \frac{5.5\ cm}{18\ cm} \approx 0.31.$

We will repeat this process for the other dyes, assuming a visual analysis gives approximate values for dyes P, R, and Y as 7 cm, 12 cm and 15 cm respectively.

Step 2

Calculate Rf values for all dyes

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The further analysis yields:

For dye P: $Rf_P = \frac{7\ cm}{18\ cm} \approx 0.39.$
For dye R: $Rf_R = \frac{12\ cm}{18\ cm} \approx 0.67.$
For dye Y: $Rf_Y = \frac{15\ cm}{18\ cm} \approx 0.83.$

With these calculations, the Rf values rank as follows:

G: 0.31
P: 0.39
R: 0.67
Y: 0.83

Step 3

Select the correct answer

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Answer

The dye that is most strongly adsorbed onto the stationary phase is dye G, as it has the lowest Rf value. In this context, since the question asks for the dye most strongly adsorbed to the stationary phase, we note the choices given in the options and we can conclude that the closest answer provided is:

B. 0.33

A paper chromatograph of four dyes, G, P, R and Y, is shown below - VCE - SSCE Chemistry - Question 4 - 2016 - Paper 1

Worked Solution & Example Answer:A paper chromatograph of four dyes, G, P, R and Y, is shown below - VCE - SSCE Chemistry - Question 4 - 2016 - Paper 1

Identify the dye adsorbed the most

Calculate Rf values for all dyes

Select the correct answer

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