Hydroxy compounds — AS & A Level Chemistry (9701) questions by topic
Hydroxy compounds questions test alcohols and phenols side by side: deducing structures from oxidation behaviour with acidified potassium dichromate(VI), drawing structural isomers of secondary alcohols, and explaining why a phenol's OH oxygen activates the benzene ring towards electrophiles.
Deduce, identify, draw and explain dominate the 36 questions drawn from 2023 to 2025 papers, worth 1 to 8 marks apiece, so a single missed step in a mechanism or isomer count can cost the whole mark. Submitting each answer for instant marking flags exactly where an explanation of electron density or a structural diagram falls short, before the habit repeats across the paper.
What examiners look for
- Examiners repeatedly note that the effect on the oxygen's electron density was often left unexplained or wrongly described as simply increased charge density.
- A recurring criticism is the omission of the benzene diazonium salt, or using concentrated HNO3 with H2SO4 where it was not required.
- Reports flag answer C as a frequent wrong choice: the electron-donating ethyl group concentrates negative charge on the oxygen rather than delocalising it, so CH3CH2O- is the stronger base and B is correct.
- Strong answers recognised that the OH oxygen's lone pair delocalises into the benzene ring, attracting and polarising the incoming electrophile.
- Candidates who drew out compound M's structure first, before deciding which alcohols resist oxidation, were more likely to identify it correctly.
May–June 2025, Paper 11
Considering only structural isomers, what is the number of alcohols of each type with the formula C5H12O? A primary=3, secondary=3, tertiary=2 B primary=4, secondary=2, tertiary=2…
Answer this question and get it marked →May–June 2025, Paper 12
Which compound cannot be oxidised by acidified potassium dichromate(VI) solution but does react with sodium metal? A (CH3)3COH B CH3COCH2CH3 C CH3CH2CH2CH2OH D CH3CH2CH(OH)CH3
Answer this question and get it marked →May–June 2025, Paper 13
The compounds shown are all produced by plants (four terpenol-type alcohols with different positions of OH and degrees of unsaturation). Each compound is warmed with acidified…
Answer this question and get it marked →May–June 2025, Paper 14
An alcohol, U, is reacted with hot acidified K2Cr2O7 solution. The organic product of the reaction contains 58.8% C, 9.8% H and 31.4% O by mass. What is the identity of alcohol U?…
Answer this question and get it marked →Which row shows a primary, a secondary and a tertiary alcohol? A primary: propan-1-ol, secondary: propan-2-ol, tertiary: propane-1,2-diol B primary: 2-methylpropan-1-ol,…
Answer this question and get it marked →May–June 2024, Paper 11
A molecule of geraniol is shown: an open-chain terpene alcohol with two C=C double bonds and a terminal CH2OH group. What is formed when geraniol is reacted with an excess of cold…
Answer this question and get it marked →Compound X is a single, pure, optical isomer. Compound X is heated with an excess of concentrated H2SO4. Only one organic product is formed. What is compound X? Four structures…
Answer this question and get it marked →Which reagents could be used to form 2-bromobutane from butan-1-ol? A bromine and ultraviolet light B concentrated sulfuric acid with potassium bromide, under reflux C…
Answer this question and get it marked →May–June 2024, Paper 12
Compound X can be oxidised to compound Y. Compound Y gives a yellow precipitate with alkaline I2(aq). What is compound X? A butan-1-ol B butan-2-ol C methylpropan-1-ol D…
Answer this question and get it marked →Which reaction will distinguish between propan-1-ol and propan-2-ol? A warming with acidified KMnO4 B warming with acidified K2Cr2O7 C dehydration, followed by reaction with…
Answer this question and get it marked →May–June 2024, Paper 41
Samples of phenol, C6H5OH, are reacted separately with sodium and with dilute nitric acid. (i) Write the equation for the reaction of C6H5OH with Na. (ii) Draw the structures of…
Answer this question and get it marked →May–June 2024, Paper 43
Samples of phenol, C6H5OH, are reacted separately with sodium and with dilute nitric acid. (i) Write the equation for the reaction of C6H5OH with Na. (ii) Draw the structures of…
Answer this question and get it marked →October–November 2024, Paper 11
Which alcohol gives only one possible oxidation product when warmed with dilute acidified potassium dichromate(VI)? A butan-1-ol B butan-2-ol C 2-methylpropan-1-ol D…
Answer this question and get it marked →October–November 2024, Paper 12
What are the only structures formed when butan-2-ol is heated with concentrated H₂SO₄? The options show sets of alkene structures formed by dehydration. A shows but-1-ene and…
Answer this question and get it marked →The compound 'leaf alcohol' is partly responsible for the smell of new-mown grass. leaf alcohol: CH₃CH₂CH=CHCH₂CH₂OH What will be formed when 'leaf alcohol' is oxidised using an…
Answer this question and get it marked →October–November 2024, Paper 13
Which alcohol gives only one possible oxidation product when warmed with dilute acidified potassium dichromate(VI)? A butan-1-ol B butan-2-ol C 2-methylpropan-1-ol D…
Answer this question and get it marked →October–November 2024, Paper 41
(a) An aqueous solution of phenol, C6H5OH, is acidic at 298 K. Explain why phenol is more acidic than water.
Answer this question and get it marked →October–November 2024, Paper 43
(a) An aqueous solution of phenol, C6H5OH, is acidic at 298 K. Explain why phenol is more acidic than water.
Answer this question and get it marked →February–March 2023, Paper 12
When illudin S is heated under reflux with an excess of acidified potassium dichromate(VI), compound M is formed. The structure of illudin S is shown: a bicyclic compound…
Answer this question and get it marked →Citric acid can be converted into tricarballylic acid in two stages. An intermediate, Q, is formed. citric acid →(stage 1)→ Q →(stage 2)→ tricarballylic acid Citric acid is…
Answer this question and get it marked →May–June 2023, Paper 11
Which reagent will react with pentan-3-ol to give a mixture of stereoisomers? A acidified potassium dichromate B concentrated sulfuric acid C ethanoic acid in the presence of a…
Answer this question and get it marked →Which row describes the type of reaction that occurs when propan-1-ol reacts to form the named carbon-containing product? carbon-containing product type of reaction --- --- --- A…
Answer this question and get it marked →How many structurally isomeric secondary alcohols are there with the molecular formula C5H12O? A 1 B 2 C 3 D 4
Answer this question and get it marked →May–June 2023, Paper 12
The general formula for a non-cyclic alcohol is CnH2n+1OH. How many different structural isomers are there for n = 3 and n = 4? n = 3 n = 4 --- --- --- A 2 2 B 2 4 C 3 4 D 3 8
Answer this question and get it marked →X, Y and Z are three isomeric alcohols. X CH3CH2CH2CH2CH2OH Y CH3CH2CH(OH)CH2CH3 Z (CH3)3C(OH)CH2CH3 Separate samples of each alcohol are warmed with a mild oxidising agent and…
Answer this question and get it marked →May–June 2023, Paper 13
Which compound is a secondary alcohol that can be dehydrated to form an alkene with Mr = 70? Four skeletal structures of alcohols are shown. A is a branched alcohol…
Answer this question and get it marked →The conversion of propan-1-ol into propan-2-ol can be completed in a two-stage synthesis. The first stage is to heat the propan-1-ol with concentrated sulfuric acid. Which reagent…
Answer this question and get it marked →May–June 2023, Paper 42
Explain why phenol is brominated much more easily than benzene is brominated.
Answer this question and get it marked →October–November 2023, Paper 11
Alcohol X gives a yellow precipitate with alkaline I2(aq). What is the structure of X? A: a dimethyl-substituted cyclohexanol with the OH on a CH carbon (a secondary alcohol…
Answer this question and get it marked →When ethanol reacts with sodium metal, ethoxide ions, CH3CH2O-, are produced. When water reacts with sodium metal, OH- ions are produced. Which statement about these reactions and…
Answer this question and get it marked →Menthol is a naturally occurring alcohol (a cyclohexane ring bearing a methyl group, an isopropyl group and an OH group). When menthol is heated with concentrated sulfuric acid it…
Answer this question and get it marked →October–November 2023, Paper 12
Which alcohol reacts with alkaline I2(aq) to produce ethanoate ions? A: ethanol. B: methylpropan-2-ol. C: propan-2-ol. D: butan-2-ol.
Answer this question and get it marked →Heating compound X, C7H14O2, under reflux with an excess of acidified potassium dichromate(VI) produces compound Y. Compound Y produces hydrogen gas with sodium metal and forms…
Answer this question and get it marked →October–November 2023, Paper 13
Alcohol X gives a yellow precipitate with alkaline I2(aq). What is the structure of X? A A cyclohexane ring with a -OH directly on a ring carbon and a CH3 group on another ring…
Answer this question and get it marked →When ethanol reacts with sodium metal, ethoxide ions, CH3CH2O-, are produced. When water reacts with sodium metal, OH- ions are produced. Which statement about these reactions and…
Answer this question and get it marked →Menthol is a naturally occurring alcohol. [The skeletal structure of menthol is shown: a cyclohexane ring bearing a CH3 group, an -OH group on an adjacent ring carbon, and an…
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