Question

What would happen to the RF value if the pigments, when using 40:60 hexanes: acetone as the developing solvent in the TLC chamber?

a. RF value would increase.
b. RF value would decrease.
c. RF value would remain unchanged.
d. RF value would vary unpredictably.

Answer 1

When using 40:60 hexanes:acetone as the developing solvent in the TLC chamber, the RF value would increase.

Step-by-step explanation:

When using 40:60 hexanes:acetone as the developing solvent in the TLC chamber, the RF value would increase.

The RF value stands for the Migration Factor, which is the ratio of the distance traveled by a particular substance to the distance traveled by the solvent front. Hexanes and acetone are both polar solvents, but hexanes are less polar than acetone. As the polarity of the solvent increases, the substances with lower polarity will travel further up the TLC plate. Therefore, with a higher proportion of acetone in the solvent mixture, the RF value would increase.

For example, if a pigment originally had an RF value of 0.4 when using hexanes as the developing solvent, the RF value would likely increase if a 40:60 hexanes:acetone mixture is used.