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Rf value question need help

Using thin layer chromatography, the question asks what happens to the Rf value if a polar solvent is used. The samples contain amino acids.

My prediction is that Rf value will increase; this is right. But I don't get the reasoning; I thought there will be more permanent dipole-dipole interation forming between the amino acids and the polar solvent, so as the solvent moves up then the amino acids will be 'pulled up' as a result However the reason is that amino acid will be more soluble are (in more polar solvent so would travel further up the plate

I am not sure why solubility is linked to the distance travelled, why is it not to do with the IMF?

Thanks
Original post by coconut64
Using thin layer chromatography, the question asks what happens to the Rf value if a polar solvent is used. The samples contain amino acids.

My prediction is that Rf value will increase; this is right. But I don't get the reasoning; I thought there will be more permanent dipole-dipole interation forming between the amino acids and the polar solvent, so as the solvent moves up then the amino acids will be 'pulled up' as a result However the reason is that amino acid will be more soluble are (in more polar solvent so would travel further up the plate

I am not sure why solubility is linked to the distance travelled, why is it not to do with the IMF?

Thanks


your answer is the same as the mark scheme, and yes, it's all to do with interparticulate forces.
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coconut64
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Original post by charco
your answer is the same as the mark scheme, and yes, it's all to do with interparticulate forces.


Is the solubility of the amino acids due to the hydrogen bond formed between the amino acids and the solvent ?

Thanks
Original post by coconut64
Is the solubility of the amino acids due to the hydrogen bond formed between the amino acids and the solvent ?

Thanks


Rather depends on the solvent ... but with a polar solvent you can certainly expect dipole -dipole IMF
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coconut64
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Original post by charco
Rather depends on the solvent ... but with a polar solvent you can certainly expect dipole -dipole IMF


So what is solubility affected by as I thought it is only affected by hydrogen bondings, are you suggesting that more permanent dipole interaction can also increase the solubility? Just a bit confused.. Also is the distance travelled by the spots dependent on the size of the molecule or solubility?
(edited 6 years ago)

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