Shapes of organic molecules; σ and π bonds: past paper questions
Real questions on shapes of organic molecules; σ and π bonds
The newest 20 of 23 written questions. Open one to see it on the real paper.
- 9701/41 · May/June 2026 · Q7b(i)[1]
Complete Table 7.1 to show the number of sp, sp 2 and sp 3 hybridised carbon atoms in propanone and in G. Table 7.1 sp sp 2 sp 3 propanone G
See it on the paper → - 9701/41 · May/June 2024 · Q6b[2]
The compound C 6 H 6 has many structural isomers. Four suggested structures of C 6 H 6 are shown in Fig. 6.1. Kekulé benzene Dewar benzene Ladenburg benzene delocalised benzene Fig. 6.1 Using Fig. 6.1, complete Table 6.1 to predict the number of carbon atoms that have sp, sp 2 and sp 3 hybridisation in Kekulé benzene,...
See it on the paper → - 9701/41 · May/June 2024 · Q6c[2]
Describe the shape of delocalised benzene. Include the geometry of each carbon, the C-C-H bond angle and the type of bond(s) between the carbon atoms and between the carbon and hydrogen atoms.
See it on the paper → - 9701/41 · May/June 2024 · Q6d[1]
Suggest why Dewar benzene and Ladenburg benzene are unstable isomers of C 6 H 6 .
See it on the paper → - 9701/42 · February/March 2024 · Q4b(ii)[2]
Pyrazine is an aromatic compound. The bonding and structure of pyrazine is similar to that of benzene. Describe and explain the shape of pyrazine. In your answer, include: • • the hybridisation of the nitrogen and carbon atoms how orbital overlap forms π bonds between the atoms in the ring.
See it on the paper → - 9701/42 · February/March 2024 · Q4b(iii)[1]
Predict the number of peaks seen in the carbon–13 NMR spectrum of pyrazine. Explain your answer.
See it on the paper → - 9701/43 · October/November 2023 · Q7b[3]
Deduce the structures of E, F and G and draw them in the boxes in Fig. 7.1.
See it on the paper → - 9701/22 · May/June 2023 · Q3c[2]
Complete Table 3.1 to show the number of sigma bonds ( σ ) and pi bonds (π) present in a molecule of X. Table 3.1 type of bond number of bonds in X sigma ( σ ) pi (π)
See it on the paper → - 9701/23 · May/June 2023 · Q5c[2]
Complete Table 5.1 to show the number of sp 2 and sp 3 hybridised carbon atoms in a molecule of X. Table 5.1 type of hybridisation sp 2 sp 3 number of carbon atoms in X
See it on the paper → - 9701/43 · May/June 2023 · Q4a[3]
State the hybridisation of the carbon atoms and the C–C–H bond angle in benzene, C 6 H 6 . Explain how orbital overlap leads to the formation of σ and π bonds in benzene.
See it on the paper → - 9701/42 · February/March 2023 · Q5a[3]
Tulobuterol contains a benzene ring in its structure. Describe and explain the shape of benzene. In your answer, include: • • • the bond angle between carbon atoms the hybridisation of the carbon atoms how orbital overlap forms v and r bonds between the carbon atoms.
See it on the paper → - 9701/22 · October/November 2022 · Q3c(i)[1]
Use the two infrared spectra and Table 3.2 to identify the functional group present only in E. Explain your answer, referring only to absorptions at frequencies greater than 1500 cm –1 . functional group explanation
See it on the paper → - 9701/22 · October/November 2022 · Q3c(ii)[1]
Use the infrared spectrum of F to identify the functional group formed when E reacts with cold dilute acidified KMnO 4 (aq). Explain your answer, referring only to absorptions at frequencies greater than 1500 cm –1 . functional group explanation
See it on the paper → - 9701/22 · October/November 2021 · Q3c(ii)[1]
State the hybridisation of the two carbon atoms between which the pi (π) bond forms.
See it on the paper → - 9701/22 · October/November 2020 · Q4d(i)[1]
Identify the bonds responsible for the absorptions marked X and Z. X Z Absorption Y shows that L has a C=C bond present in the R group. The student decided to treat L with hot concentrated acidified potassium manganate( VII ). The products of the reaction are shown. O L O O hot concentrated acidified KMnO 4 R O OH...
See it on the paper → - 9701/42 · October/November 2020 · Q7a[4]
Describe the structure of a benzene molecule, C 6 H 6 . Your answer should include: ● the shape of the molecule ● the relative lengths of the C–C bonds ● bond angles ● the hybridisation of the carbon atoms ● the overlap between orbitals that produces each type of bond present.
See it on the paper → - 9701/21 · October/November 2019 · Q4a(ii)[1]
State the hybridisation of the carbon atom labelled with an asterisk, *. CH 3 H 3 C C O C * CH 3 H
See it on the paper → - 9701/21 · October/November 2019 · Q4b(iii)[1]
Give the balanced equation for the reaction of (CH 3 ) 3 CCHO with NaBH 4 to form S. Use [H] to represent an atom of hydrogen provided by NaBH 4 .
See it on the paper → - 9701/42 · October/November 2019 · Q7b(i)[3]
Describe what is meant by each of these terms. primary structure secondary structure tertiary structure
See it on the paper → - 9701/42 · October/November 2019 · Q7b(ii)[1]
Name the forces or bonds responsible for holding together the primary structure of a protein molecule.
See it on the paper →
What examiners said
This question was answered well. The structures of E and G were normally correct. A common error was placing the positive charge on the incorrect N on the diazo compound F.
— Examiner report, October/November 2023, 9701/43 Q7(b) (Cambridge)
Most candidates described the correct number of pi bonds present in X; the correct number of sigma bonds was seen less frequently. Seven, nine and ten sigma bonds were common incorrect answers.
— Examiner report, May/June 2023, 9701/22 Q3(c) (Cambridge)
Candidates found this to be difficult. Some candidates produced some good answers. It was very important for candidates to take careful note of the sentence, ‘Explain how orbital overlap leads to the formation of σ and π bonds in benzene’; this was an indication of the question requirements.
— Examiner report, May/June 2023, 9701/43 Q4(a) (Cambridge)
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