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CAIE A Level Chemistry 9701

An introduction to organic chemistry questions

Exam-style questions on An introduction to organic chemistry, ordered from foundation to challenge. Pick one, write your answer the way you would in the exam, and it comes back marked against the mark scheme, point by point.

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Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.

  1. Compare5 marksStandardThe molecular formula C4H8 represents an alkene, but-2-ene (CH3CH=CHCH3), while C4H9Cl represents a chloroalkane, 2-chlorobutane (CH3CHClCH2CH3). Compare the structural features that cause but-2-ene to exhibit…
  2. Suggest4 marksStandardA student reacts ethanoyl chloride with ethanol. The reaction produces an ester and hydrogen chloride. Suggest the type of mechanism for this reaction, and explain why the reaction is described by this term.
  3. Describe5 marksStandardA straight-chain compound has the formula C6H11N and contains a nitrile functional group. Describe how the systematic name of this compound is deduced from its structural formula, and state the name.
  4. Suggest4 marksStandardAn ester is formed when methanol reacts with butanoic acid. State the systematic name of this ester and give its displayed formula. Suggest one physical property of this ester that is different from the properties of…
  5. Describe5 marksStandardCyclohexane, C6H12, is a cyclic alkane. Describe the shape and bond angles of the carbon skeleton in cyclohexane, and explain why the carbon atoms in cyclohexane are not all in the same plane. In contrast, describe the…
  6. Explain4 marksStandardA student investigates the naming of organic compounds. Explain how the functional groups present in the following compounds relate to their systematic names and the class of compound to which they belong. (a)…
  7. Suggest4 marksStandardIn organic chemistry, redox equations are often written using the symbols [O] and [H] rather than full electron transfer. Suggest what each symbol represents and how they are used to show oxidation and reduction in…
  8. Compare5 marksStandardCompare the organic compounds ethene (C2H4) and ethane (C2H6) in terms of the hybridisation of their carbon atoms, the bond angles present, the arrangement of atoms around each carbon atom, the type of carbon–carbon…
  9. Describe5 marksStandardDescribe the meaning of structural isomerism and of stereoisomerism, and describe how each of these two main types of isomerism is subdivided.
  10. Explain4 marksStandardTwo organic reactions are described below. Reaction 1: Benzene reacts with bromine in the presence of FeBr3 catalyst to form bromobenzene. The Br+ ion is generated as the electrophile, which is attacked by the π…
  11. Explain4 marksStandardExplain why the carbon atoms in ethene (C2H4) have a planar arrangement, whereas the carbon atoms in ethane (C2H6) have a non-planar arrangement. In your answer, refer to the hybridisation of the carbon atoms and the…
  12. Explain4 marksStandardExplain what is meant by (i) a chiral centre and how it gives rise to optical isomerism, and (ii) the origin of geometrical (cis/trans) isomerism in alkenes. In your answer, give an example of a molecule that exhibits…
  13. Explain4 marksStandardBenzene, C6H6, has a regular hexagonal planar structure with all C–C–C bond angles equal to 120°. Explain this shape in terms of the hybridisation of the carbon atoms and the delocalisation of electrons.
  14. Suggest4 marksStandardEthane, C2H6, and ethene, C2H4, both contain only carbon and hydrogen atoms. In ethane each carbon atom is bonded to four other atoms; in ethene each carbon atom is bonded to three other atoms. Suggest why the bond…
  15. Compare5 marksStandardBenzene is an aromatic hydrocarbon with molecular formula C6H6. Another hydrocarbon, hexa-1,3,5-triene, also has molecular formula C6H6. Compare the bonding and shape of benzene with those of hexa-1,3,5-triene.
  16. Suggest4 marksStandardThe structural formula of 2-chlorobutane is CH3CHClCH2CH3. Suggest why 2-chlorobutane has two optical isomers (enantiomers) but no geometrical (cis/trans) isomers.
  17. Compare5 marksStandardCompound A has the structural formula CH3CH2CH2CN. Compound B has the structural formula CH3CH2NH2. Compare compounds A and B in terms of their molecular formulas, functional groups and systematic names.
  18. Explain4 marksStandardA student is given the IUPAC name butanenitrile. Explain how the name butanenitrile indicates both the functional group and the carbon skeleton of the compound. Deduce the molecular formula of butanenitrile.
  19. Compare5 marksStandardCompare propan-1-ol and propanal in terms of their functional groups, general formulas, systematic names, and one physical property that differs between the two compounds.
  20. Describe5 marksStandardDescribe how the reaction of propene with bromine differs from the reaction of propane with bromine, in terms of the type of reaction, the conditions needed, and the type of mechanism involved.
  21. Compare5 marksStandardA student carries out two separate organic reactions. Reaction 1: An excess of methylamine, CH3NH2, is added to a solution of chloroethane, CH3CH2Cl, in ethanol at room temperature. Reaction 2: Ethene gas, CH2=CH2, is…
  22. Explain4 marksStandardIn organic chemistry, reactions are classified by the types of reagents and the bond fission involved. Explain the following terms: nucleophile, electrophile, homolytic fission, heterolytic fission.
  23. Compare5 marksStandardA chiral drug molecule is synthesised as a racemic mixture. Compare the two enantiomers of this drug in terms of their physical properties, their effect on plane-polarised light, and their biological activity. Explain…
  24. Compare5 marksStandardCompare electrophilic substitution and addition-elimination mechanisms in organic reactions. In your answer, refer to the type of substrate each mechanism typically occurs with, the nature of the attacking species, and…
  25. Suggest4 marksStandardA student is told that a compound has the molecular formula C6H11N and contains a nitrile functional group. Suggest a displayed formula (showing all bonds) for this compound and give its systematic name.
  26. Describe5 marksStandardWhen ethanoyl chloride, CH3COCl, is added to water, it reacts vigorously to form ethanoic acid and hydrogen chloride. Describe the mechanism of this reaction, including the role of the water molecule and the overall…
  27. Explain4 marksStandardA new chiral drug is synthesised by a non-stereoselective method, producing a racemic mixture. The drug has one chiral centre. One enantiomer is therapeutically active, while the other is inactive and causes harmful…
  28. Explain7 marksChallengeEthyne, C2H2, is a straight-chained molecule in which each carbon is bonded to one hydrogen and to the other carbon by a triple bond. Ethene, C2H4, is a straight-chained molecule in which each carbon is bonded to two…
  29. Explain7 marksChallengeEthene reacts with bromine to form 1,2-dibromoethane. Explain, in terms of the type of reaction, the type of bond fission, and the role of the bromine molecule, why this reaction occurs readily and why it is not a…
  30. Describe7 marksChallengeTwo organic compounds are described below. Compound A is an aliphatic compound with a straight chain of four carbon atoms. It contains a chlorine atom attached to the second carbon atom and a hydroxyl group attached to…
  31. Compare6 marksChallengeA student draws the displayed formula of a molecule with the structure: a chain of two carbon atoms, each carbon carrying hydrogen atoms, and one carbon also bonded to an -OH group. (a) State the general formula of the…
  32. Describe7 marksChallengeIbuprofen contains a chiral centre. The (S)-enantiomer is active as an analgesic, whereas the (R)-enantiomer is inactive. Ibuprofen is usually manufactured as a racemic mixture. Describe the relevance of chirality to…
  33. Compare6 marksChallenge1-bromo-2-methylpropane can undergo reactions with aqueous sodium hydroxide and with ethanolic sodium hydroxide. Compare these two reactions in terms of the type of reaction, the conditions, and the role of the…
  34. Describe7 marksChallengeIsomerism is a key concept in organic chemistry. Explain the meaning of isomerism and describe the different types that can occur. In your answer, you must: define structural isomerism and stereoisomerism, explaining…
  35. Explain7 marksChallengeExplain why the functional group in propan-1-ol, CH3CH2CH2OH, determines its physical and chemical properties, making it different from propane, C3H8. In your answer, refer to the effect of the functional group on…
  36. Describe7 marksChallengeTwo reactions are used in the synthesis of a pharmaceutical compound. Reaction 1: Methylbenzene is reacted with a mixture of concentrated nitric acid and concentrated sulfuric acid at 50°C to form…
  37. Describe7 marksChallengeDescribe the hybridisation, shape, and bond angle of the carbon atoms in methane (CH4), ethene (C2H4), and ethyne (C2H2). In your answer, state whether each molecule is planar and classify each as straight-chained…
  38. Explain7 marksChallengeA student is studying the isomers of two compounds, X and Y. X has the molecular formula C4H9Cl. The student draws the structural formulae of two isomers of X, A and B. A: CH3CH2CH2CH2Cl B: CH3CHClCH2CH3 (a) State the…
  39. Describe7 marksChallengeConsider the reaction between a primary amine, such as ethylamine (CH3CH2NH2), and an acyl chloride, such as ethanoyl chloride (CH3COCl). Describe this reaction using the following terminology from organic chemistry…
  40. Describe7 marksChallengeDescribe and explain the shape and bonding in benzene, C6H6, and in pyridine, C5H5N. In your answer, refer to the hybridisation of the carbon and nitrogen atoms, the types of bonds present, and the delocalisation of…
  41. Describe7 marksChallengeThe displayed formula of an organic compound is given below. H2N-CH2CH2CH3 (a) Describe the functional group present in this compound. (b) State the systematic name of this compound. (c) Deduce the molecular formula of…
  42. Compare6 marksChallengeEthene, C2H4, and ethane, C2H6, are both hydrocarbons but their molecules have different shapes. Compare the shapes of the two molecules, including the bond angles, the hybridisation of the carbon atoms, and the…