Question

4. Calculate the percent recovery for each component if 0.047 g of fast component and 0.038g of slow component, when you started with 0.103 g of mixture.

5. What is the Rf value for slow component using 30% ethyl acetate/hexane? Distance of first spot 0.3 cm, distance of the second spot 4.7 cm and the solvent traveled 6.1 cm.

These questions relate to a TLC and colum chromatography organic chemistry lab

Answer 1

4. (Insufficient information is given. Hence, only way to solve question is given below)

Composition of mixture (wt. of each component in mixture) is required to calculate percent recovery.

Percent recovery is calculated using following expression:

Percent recovery =100 x (wt. of compound recovered) / (wt. of original material in mixture)

Substitute wt. of recovered compound (0.047g for fast component and 0.038 g for slow component) in numerator and wt. of original compound in denominator (not given) to calculate percent recovery.

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5.

Slow moving component travels less distance on TLC. Therefore, distance travelled by slow moving component is 0.3 cm. Distance travelled by solvent front is 6.1 cm. Calculate Rf value of slow moving component using following expression:

Rf = (distance travelled by spot) / (distance travelled by solvent front)

Rf = (0.3 cm) / (6.1 cm)

Rf = 0.05

Hence, Rf of slow moving component is 0.05