A student used paper chromatography to separate two components, I and II, in a solution. A spot of the solution was initially placed at the origin.The distances measured by the student on the chromatogram are shown in the table below. DistanceSolvent front7.5 cmComponent I6.0 cmComponent II1.5 cm behind Component I The Rf value of component II is closest toa.0.25b.0.20c.0.60d.0.80
Question
A student used paper chromatography to separate two components, I and II, in a solution. A spot of the solution was initially placed at the origin.The distances measured by the student on the chromatogram are shown in the table below. DistanceSolvent front7.5 cmComponent I6.0 cmComponent II1.5 cm behind Component I The Rf value of component II is closest toa.0.25b.0.20c.0.60d.0.80
Solution 1
The Rf value, or retention factor, is calculated by dividing the distance traveled by the substance by the distance traveled by the solvent.
From the table, we know that the solvent front traveled 7.5 cm.
Component II is said to be 1.5 cm behind Component I, which traveled 6.0 cm. Therefore, Component II traveled 6.0 cm - 1.5 cm = 4.5 cm.
So, the Rf value for Component II is 4.5 cm / 7.5 cm = 0.60.
Therefore, the answer is c. 0.60.
Solution 2
The Rf value, or retention factor, in chromatography, is calculated by dividing the distance traveled by the substance by the distance traveled by the solvent.
In this case, for component II, the distance traveled by the substance is not directly given. However, we know that component II is 1.5 cm behind component I, which traveled 6.0 cm. Therefore, component II traveled 6.0 cm - 1.5 cm = 4.5 cm.
The distance traveled by the solvent (the solvent front) is 7.5 cm.
So, the Rf value for component II is 4.5 cm / 7.5 cm = 0.60.
Therefore, the answer is c. 0.60.
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