The students in a scheduled laboratory were going to separate compounds A, B, an

Question

The students in a scheduled laboratory were going to separate compounds A, B, and C by column chromatography. The students constructed a column in the same way that you will do in experiment #9 and used silica gel as the stationary phase. The students had three solvents available to elute the compounds from their columns: 100% hexane; 50/50, v/v hexane/ethyl acetate, and 100% ethyl acetate. In order to obtain complete separation of these three compounds they had to use all three of the solvents. Which solvent should be used first, which solvent should be used second, and which solvent should be used third? Explain your answer. Which compound will elute from the column first, which compound will elute from the column second and which compound will elute from the column last? Explain your answer.

Explanation / Answer

Polar compounds strongly bind with stationary phase, compared to non-polar compounds.Non polar comound elutes first           

   a)           100% Hexane first used,  

                                 second hexane /ethyl acetate.   

                                     Third Ethylacetate should be used.

                       b)         Compound A [non-polar] weakly bind with stationary phase, so first eluted by

                              100%    n- Hexane solvent[non-polar solvent]

                             Compound B second Eluted [moderatelly polar] by hexane+ethylacetate mixture

                             Compound C   [Highly polar] Strongly bind with stationary phase, Eluted by 100%Ethylacetate last

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.