Question

The layer paper chromatograpy is performed on an unknown substance. Three solvents were tested, and the corresponding $R_f$ factors were measured: $1-propanol,R_f=1.15;hexane,Rf=0.32$; acetonitrile, $R_f=1.74$.
Which of the solvents would best separate the unknown substance with an $R_f=1.69$ from a known substance with an $R_f=1.53$?

• A. A mixture of the $1-propanol$ or acetonitrile would work equally effectively at separating the unknown substance from the known substance.
• B. The acetonitrile would allow for the most solute-solvent interaction with the unknown without any interference from the known substance.
• C. The $1-propanol$ would allow the unknown to completely separate from the known substance.
• D. The hexane would allow the unknown to completely separate from the known substance.

Answer 1

The correct option is A A mixture of the $1-propanol$ or acetonitrile would work equally effectively at separating the unknown substance from the known substance.

Since, the $R_f$ values of 1-propanol and acetonitrile is very high that means the unknown compound is polar;

so, we have to use mixture of 1-propanol or acetonitrile which would work equally effectively to separate the mixture.