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CAIE IGCSE Chemistry 12.3 Chromatography Questions

Practise setting up paper chromatography, interpreting spots and solvent fronts and calculating or comparing Rf values to identify mixture components.

Syllabus
2026–2028
Course
Chemistry 0620

Exam points

  • draw a pencil baseline above the solvent and place small concentrated sample spots on it
  • interpret separated spots and compare unknown positions or Rf values with standards
  • calculate Rf as distance travelled by the substance divided by distance travelled by solvent

Covered syllabus points

12.3.1—Paper chromatography is used to12.3.2—Interpret simple chromatograms to12.3.3—Paper chromatography is used to12.3.4—And use the equation for Rf: Rf =

Question 1

[Maximum number: 1]

Which statement about paper chromatography is correct?

A

A solvent is needed to dissolve the paper.

B

Paper chromatography separates mixtures of solvents.

C

The solvent should cover the baseline.

D

The baseline should be drawn in pencil.

Question 2

[Maximum number: 1]

The chromatogram obtained using four substances, J, K, L and M, is shown.

Figure for Question 2 — CAIE IGCSE Chemistry

Which statement about M is correct?

A

It is a mixture of J and K only.

B

It is a pure substance.

C

It is a mixture of J, K and L.

D

It is a mixture of J, K and an unknown substance.

Question 3

[Maximum number: 1]

Which statement about chromatography is correct?

A

It is not possible for two different substances to have the same RfR_{\mathrm{f}} value.

B

It is only possible to use chromatography on substances which have a colour.

C

It is possible to use chromatography on colourless substances using a locating agent.

D

The RfR_{\mathrm{f}} value of a substance = the distance travelled by the solvent  the distance travelled by the substance =\frac{\text { the distance travelled by the solvent }}{\text { the distance travelled by the substance }}

Question 4

[Maximum number: 1]

39Rf39 R_{\mathrm{f}} values are used to identify unknown substances using paper chromatography.
Which statements about RfR_{\mathrm{f}} values are correct?
1Rf1 \quad R_{\mathrm{f}} values are always less than 1.0.
2Rf2 \quad R_{\mathrm{f}} value = distance travelled by solvent ÷ distance travelled by unknown substance.
3 The higher the RfR_{\mathrm{f}} value, the further the unknown substance travels.
4Rf4 R_{\mathrm{f}} values are not affected by the solubility of the unknown substance.

A

1 and 2

B

1 and 3

C

2 and 3

D

3 and 4

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