Question about chromatography....?

Question

Is it possible for two components of a dye mixture to have the same Rf values for a given solvent system but have different colors?

I need to know this for a lab question, but I'm not entirely sure what it is asking or how to answer it. I know what Rf value is, but not what the question means. The lab used markers and dyes, if that helps any. Thanks.

Answer 1

yes, two components could have the same Rf value but different colors. color alone does not indicate that two compounds will have different Rf values

Answer 2

Sure.

Rf is a function of relative polarity (compared to the stationary and mobile phases). Color is a function of orbital energies. Both reflect molecular structure, but not in the same way.

Two components in a mixture that have an identical Rf value are 2 components that aren't separated. So, if you have yellow and red components, you might see them unseparated as an orange spot (but, not all orange spots are necessarily multi-components!).

The most obvious places where separation doesn't occur is for the Rf values of... 0 and 1.

You might want to meditate on how to differentiate between an unseparated mixture and a pure compound of the same color.

Answer 3

Components are identified in cromatography based on their colour and Rf values.

So two components can have same Rf values and different colours and vice versa.

Answer 4

The question means, "can two different dyes travel up your chromatography strip at the same speed in at least one set of conditions?"

Yes, they can, but good luck finding that unique set of conditions.

Answer 5

it's possible depending on solvent. it means they have about the same polarity.

Answer 6

yes they can because they may have similar polarity ,different colors debend on orbital energy not on polarity