Chemistry 9701 · AS & A Level · Analytical techniques

Analytical techniques — practice question

Chromatography is a vital analytical method in chemistry. There are several techniques that fall under the broad heading of chromatography.
(a(i))[1]

Explain the meaning of partition in chromatography.

(a(ii))[1]

Explain the meaning of adsorption in chromatography.

(b(i))[1]

Ring the spot that did not dissolve in solvent 1.

(b(ii))[1]

Using solvent 1, label the spots that were not resolved as A and B.

(c(i))

Deduce the identity of $X$, and give a reason.

(c(ii))

When the relative heights of the $M$ and $M+1$ peaks are 9 and 0.3 respectively, calculate the value of $p$. Use that result together with the $m/e$ value of the molecular ion peak to calculate the value of $q$, and hence the compound’s molecular formula. Show your working.

(c(iii))[4]

Suggest a formula for the ion that gives rise to the peak labelled $R$.

(d(i))

In the fragmentation of alcohols that takes place in a mass spectrometer, small stable neutral molecules can sometimes be formed. Suggest the identity of one such molecule, with an $M_r$ less than 30.

(d(ii))[2]

In the fragmentation of alcohols that takes place in a mass spectrometer, small stable neutral molecules can sometimes be formed. Suggest the identity of another such molecule, with an $M_r$ less than 30.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: Partition: separation by differing solubilities in two phases

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