R3.3 Exam Practice
Organic Chemistry
Section B: Data Analysis
Show all working.
Question 1: Reaction Pathways Deduce
5 marksEthanol can be converted to several organic products.
(a) State the reagent and conditions to oxidise ethanol to ethanal. [2]
(b) State what further oxidation of ethanal produces. [1]
(c) State the reagent and conditions for dehydration of ethanol to ethene. [2]
Show Mark Scheme
(a) Acidified potassium dichromate (K₂Cr₂O₇/H₂SO₄) [1]; distil immediately to prevent further oxidation [1]
(b) Ethanoic acid (CH₃COOH) [1]
(c) Concentrated H₂SO₄ or Al₂O₃ catalyst [1]; heat/reflux at ~170°C [1]
Section C: Structured Questions
Show all working.
Question 2: Nucleophilic Substitution HL Explain
5 marks(a) Define nucleophile. [1]
(b) Distinguish between SN1 and SN2 mechanisms. [2]
(c) Predict which mechanism a tertiary halogenoalkane would follow. Justify. [2]
Show Mark Scheme
(a) An electron-pair donor / species with a lone pair that attacks an electron-deficient carbon [1]
(b) SN1: two-step, carbocation intermediate, rate depends on [substrate] only [1]; SN2: one-step concerted, rate depends on [substrate][nucleophile] [1]
(c) SN1 [1]; tertiary carbocation is stabilised by three alkyl groups (inductive effect), and steric hindrance prevents SN2 backside attack [1]
Question 3: Organic Reduction & Synthesis HL Deduce
5 marksA chemist needs to synthesise phenylamine starting from benzene, and propan-1-ol starting from propanoic acid.
(a) State the reagents and conditions required to convert benzene to nitrobenzene. [2]
(b) Outline the two-stage reduction process to convert nitrobenzene to phenylamine, stating the reagents for each stage. [2]
(c) Identify a suitable reducing agent for the reduction of propanoic acid to propan-1-ol, and explain why sodium borohydride (NaBH4) is not suitable. [1]
Show Mark Scheme
(a) Concentrated HNO3 and concentrated H2SO4 [1]; heat at 50 degrees C [1]
(b) Stage 1: Tin (Sn) and concentrated HCl (heated under reflux) [1]; Stage 2: Sodium hydroxide (NaOH) solution [1]
(c) Lithium aluminium hydride (LiAlH4) in dry ether [1] (NaBH4 is a weaker reducing agent and cannot reduce carboxylic acids)
⚡ Try Exam Mode
Timed, one-question-at-a-time practice with a full score breakdown. Pick topics and test yourself under real exam conditions.
Start Exam Mode