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A student measures the solvent height on a TLC plate as 11.5cm. Spot A was measured...

A student measures the solvent height on a TLC plate as 11.5cm. Spot A was measured at a height of 4.7 cm. spot B at 2.3 cm, and spot C at 8.2. What are the Rf values for spots A, B,and C?

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Answer #1

Retention factor (Rf) value for TLC is defined as,

Rf = Migration distance of spot of compound / Migration distance of solvent.

Migration distance of solvent = Solvent height = 11.5 cm

1) For compound A, migration distance = height of spot = 4.7 cm.

(Rf)A =   4.7 / 11.5

(Rf)A =   0.4087

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2) For compound B, migration distance = height of spot = 2.3 cm.

(Rf)B =   2.3 / 11.5

(Rf)B =   0.2

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3) For compound C, migration distance = height of spot = 8.2 cm.

(Rf)C =   8.2 / 11.5

(Rf)C =   0.7130

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