13.2. Characteristic organic reactions
A subsection of Chemistry, 9701, through 13. An introduction to AS Level organic chemistry
Listing 10 of 29 questions
Many organic reactions are substitution reactions in which the number of carbon atoms in the organic compound is unchanged. What is meant by the term substitution reaction? One example of a substitution reaction is the formation of an alcohol from a halogenoalkane. Write a balanced equation for the formation of ethanol from bromoethane. State the conditions for this reaction. In a few organic reactions, the product contains one more carbon atom than the starting material. Write the equation for a reaction in which the organic compound bromoethane, which contains two carbon atoms, is converted into an organic compound which contains three carbon atoms. State the conditions for this reaction. Ethanol may be converted into propanoic acid in a three-stage process which uses ethanol as the only organic compound. C2H5OH step I K step II L step III C2H5CO2H Give the structural formulae of the intermediate compounds K and L. K L State the reagentused and give the essential conditionfor step I and for step III. step I reagentconditionstep III reagentcondition
9701_s06_qp_2
THEORY
2006
Paper 2, Variant 0
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Phenol and chlorobenzene are less reactive towards certain reagents than similar non-aromatic compounds. Thus hexan-1-ol can be converted into hexylamine by the following two reactions, I II CH3(CH2)5OH CH3(CH2)5Cl CH3(CH2)5NH2 hexan-1-ol 1-chlorohexane hexylamine whereas neither of the following two reactions takes place. OH Cl NH2 Suggest reagents and conditions for reaction I, , reaction II. . What type of reaction is reaction II? Suggest a reason why chlorobenzene is much less reactive than 1-chlorohexane. Phenylamine can be made from benzene by the following two reactions. NH2 NO2 III IV Suggest reagents and conditions for reaction III, , reaction IV. . State the type of reaction for reaction III, , reaction IV. . Suggest a reagent that could be used to distinguish phenylamine from hexylamine. reagent and conditions observation with phenylamine observation with hexylamine Phenylamine is used to make azo dyes. In the following boxes draw the structural formula of the intermediate D and of the azo dye E. D E NH2 NaNO2 + HCl in NaOHT < 5°C OH CH3 CH3
9701_s09_qp_4
THEORY
2009
Paper 4, Variant 0
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Organic reactions involve substances which may be atoms, molecules, ions or free radicals. We also apply the terms electrophilic, nucleophilic, addition, elimination and substitution to organic reactions. Consider the following reactions. CH4 + Cl 2 CH3Cl + HCl reaction 1 CH3CH2OH CH2=CH2 + H2O reaction 2 CH3I + OH– CH3OH + I – reaction 3 CH3COCH3 + HCN CH3C(OH)(CN)CH3 reaction 4 Using the terms mentioned above, state as clearly as you can the nature of each of the following reactions. reaction 1 reaction 2 By considering the four reactions above, suggest a formula for each of the following substances. In each case, state which reaction you are considering. one substance that is an addition product reaction addition product one substance that is a leaving group reaction leaving group one substance that behaves as an electrophile reaction electrophile What is meant by the term nucleophile? Reactions 3 and 4 involve nucleophiles. For each reaction, give the formula of the nucleophile. reaction 3 reaction 4 One characteristic reaction of ethene is its ability to decolourise bromine. CH2=CH2 + Br2 BrCH2CH2Br In this reaction, ethene behaves as a nucleophile. Suggest an explanation for how ethene can behave in this way.
9701_s10_qp_23
THEORY
2010
Paper 2, Variant 3
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Organic chemistry is the chemistry of carbon compounds. The types of organic reactions that you have studied are listed below. addition elimination hydrolysis oxidation reduction substitution Addition and substitution reactions are further described as follows. electrophilic nucleophilic free radical Complete the table below. Fill in the central column by using only the types of reaction given in the lists above. Use both lists when appropriate. In the right hand column give the formulaof the reagentyou would use to carry out the reaction given. organic reaction type of reaction reagentCH3CH2CH2CH2Br → CH3CH2CH2CH2NH2 CH3CH2CH2CH2OH → BrCH2CH2CH2CH2OH CH3COCH3 → CH3C(OH)(CN)CH3 CH3CH(OH)CH2CH3 → CH3CH=CHCH3
9701_s13_qp_21
THEORY
2013
Paper 2, Variant 1
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Below is a list of species which can react with organic compounds. CN– HCl Cl H2O CO3 2– From the list, identify a species which can react with ethane. From the list, identify two species which can attack the π bond in ethene. From the list, identify a species which can be used to distinguish between solutions of propanoicacid and propan-1-ol. Describe any relevant observations. Cl can be made from Cl 2. Describe the conditions required for this process. Name this process. Name an organic functional group which reacts with a nucleophile in an addition reaction. Name an organic functional group which tends to react with a nucleophile in an SN1 substitution mechanism. But-1-ene reacts with steam in the presence of concentrated phosphoric acid to form two isomers of molecular formula C4H10O. Each reaction occurs via a different intermediate ion. Draw the structure of both intermediate ions.  Circle the more stable intermediate ion drawn in . Explain your answer. 
9701_s20_qp_21
THEORY
2020
Paper 2, Variant 1
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Organic chemistry is the chemistry of carbon compounds. The types of organic reactions that you have studied are listed below. addition elimination hydrolysis oxidation reduction substitution Addition and substitution reactions are further described as follows. electrophilic nucleophilic free radical Complete the table below. Fill in the central column by using only the types of reaction given in the lists above. Use both lists when appropriate. In the right hand column give the nameor formulaof the reagentyou would use to carry out the reaction given. organic reaction type of reaction reagentCH3CHO → CH3CH(OH)CN CH3CH2CH2CH3 → CH3CH2CHBrCH3 CH3CH(OH)CH3 → CH3CH=CH2 CH3CH=CH2 → CH3CH(OH)CH2OH
9701_w08_qp_2
THEORY
2008
Paper 2, Variant 0
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Questions Discovered
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