Chromatograms for a mixture of compounds A and B were obtained under the same fl

Question

Chromatograms for a mixture of compounds A and B were obtained under the same flow rate and chromatographic conditions on two different columns of equal length. The image of the grah is at this web address: https://s3.amazonaws.com/answer-board-image/7cb36edd-92bc-4ceb-961c-829c28b502f6.jpeg

Which column has more theoretical plates? (1,2, or same)
Which column gives higher resolution? (1,2, or same)
Which column has a larger plate height? (1,2, or same)
Which column gives a greater relative retention? (A, B, or same)
Which compound has a higher capacity factor? (A, B, or same)
Which compound has a smaller partition coefficient? (A, B, or same)
Which compound spends more time in the mobile phase? (A, B, or same)
Numerically estimate the selectivity factor.

Explanation / Answer

Which column has more theoretical plates?

column 1(peaks elutting at same time are narrower in column 1)

Which column gives higher resolution?

Column 1 (there is better separation between peaks)

Which column has a larger plate height?

Column 2 H = L/N. Since the length is the same and the N for col. 1 is larger, H for col. 2 will

be larger

Which column gives a greater relative retention?

There is no difference (since the retention times and the mobile phase elution time are the same

for both columns)

Which compound has a higher capacity factor?

The capacity factor, k' is the same in all chromatography

Which compound has a smaller partition coefficient?

Compound A (elutes earlier)

Which compound spends more time in the mobile phase?

There is no difference

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