Answer :
Answer:
The substance is a mixture
Explanation:
The question lets us know that when solvent X was used as the mobile phase, we obtained only one spot. This may deceive us into thinking that the substance is pure since a pure substance has only one spot on a chromatogram.
However, the same substance yields three spots with solvent Y. This shows that the unknown sample is a mixture of substances and solvent X was unable to fully separate the mixture.