A Level Chemistry (A2) chapter 10: Hydroxy compounds MCQs with answers
By Team Megalecture · Updated 4 Nov 2026
50 exam-style questions on Hydroxy compounds, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.
Try each one, then open the answer. These ten stay the same; the test draws new ones every time.
1. An alcohol Y (Mr 104) contains only –OH groups as functional groups. It reacts with excess ethanoyl chloride, and every –OH group is converted into an ester group. The organic product has Mr 188. How many –OH groups does each molecule of Y contain?
A
1
B
2
C
3
D
4
Show answer
Answer: B. Each –OH → –OCOCH3 replaces H (1) by COCH3 (43), an increase of 42. The total increase is 188 − 104 = 84 = 2 × 42, so Y has two –OH groups.
2. 2-methylpropan-2-ol, (CH3)3COH, is not oxidised by acidified potassium dichromate(VI). What happens when it is mixed with ethanoyl chloride at room temperature?
A
no reaction, because tertiary alcohols have no H on the carbon bearing –OH
B
it is oxidised to a ketone and ethanoyl chloride is reduced to ethanal
C
it forms the ester CH3COOC(CH3)3 and HCl
D
it forms an alkene and ethanoic acid
Show answer
Answer: C. Esterification breaks the O–H bond of the alcohol, not a C–H bond on the carbon bearing –OH, so tertiary alcohols react too. The missing H on that carbon only explains why they resist oxidation.
3. When ethyl ethanoate is prepared from ethanol and ethanoyl chloride, the ethanol and apparatus must be dry. Why?
A
water reacts with ethanol to form ethoxide ions
B
water catalyses the reverse reaction, turning the ester back into ethanol
C
water dissolves the ester, which is then lost as a vapour
D
water hydrolyses ethanoyl chloride to ethanoic acid, lowering the yield of ester
Show answer
Answer: D. Ethanoyl chloride reacts readily with water at room temperature: CH3COCl + H2O → CH3COOH + HCl. Any water therefore uses up the acyl chloride.
4. 1.88 g of phenol is melted and reacts completely with excess sodium. What volume of hydrogen, measured at room conditions, is given off?
A
120 cm3
B
240 cm3
C
480 cm3
D
960 cm3
Show answer
Answer: B. 2C6H5OH + 2Na → 2C6H5ONa + H2; n(phenol) = 1.88 ÷ 94.0 = 0.0200 mol, so n(H2) = 0.0100 mol = 240 cm3. 480 cm3 forgets that two phenol molecules give one H2.
5. Benzenediazonium chloride is added to phenol dissolved in NaOH(aq) below 10 °C. Which statement describes the product?
A
a colourless compound, C6H5–NH–C6H4OH, with the rings joined by one N atom
B
phenol and nitrogen gas, because the diazonium ion is hydrolysed by the alkali
C
a coloured compound, C6H5–N=N–C6H4OH, with –OH at the 4-position
D
a white precipitate of 2,4,6-trichlorophenol, formed by the chloride ions
Show answer
Answer: C. This is a coupling reaction: the diazonium ion acts as an electrophile and substitutes at the 4-position of the phenoxide ring, forming 4-hydroxyazobenzene, a yellow-orange azo dye. Hydrolysis to phenol needs warming, not cold alkaline conditions.
6. 4-methylphenol is shaken with excess bromine water. What is the organic product?
A
2,4,6-tribromo-3-methylphenol
B
3,5-dibromo-4-methylphenol
C
2-bromo-4-methylphenol
D
2,6-dibromo-4-methylphenol
Show answer
Answer: D. The –OH group directs to the 2-, 4- and 6-positions. Position 4 already carries the methyl group, so bromine substitutes at 2 and 6, using two moles of Br2. 3,5-substitution would need 3-directing groups.
7. 9.30 g of phenylamine is converted into phenol by forming the diazonium salt with NaNO2 and dilute HCl below 10 °C and then warming the solution. The overall yield is 65%. What mass of phenol is obtained?
A
6.05 g
B
6.11 g
C
9.40 g
D
14.5 g
Show answer
Answer: B. n(C6H5NH2) = 9.30 ÷ 93.0 = 0.100 mol; phenol Mr = 94.0, so 0.100 × 0.65 × 94.0 = 6.11 g. 6.05 g takes 65% of the phenylamine mass, and 9.40 g ignores the yield.
8. 3.00 g of propan-1-ol (Mr 60.0) is mixed with 3.14 g of ethanoyl chloride (Mr 78.5). What is the maximum mass of propyl ethanoate (Mr 102.0) that can form?
A
2.04 g
B
4.08 g
C
5.10 g
D
9.18 g
Show answer
Answer: B. n(propan-1-ol) = 0.0500 mol and n(CH3COCl) = 0.0400 mol; the ratio is 1 : 1, so the acyl chloride is limiting: 0.0400 × 102.0 = 4.08 g. 5.10 g uses the alcohol, which is in excess.
9. Cyclohexanol, C6H11OH, reacts with ethanoyl chloride at room temperature. What is the molecular formula of the organic product?
A
C8H12O2
B
C8H16O2
C
C8H14O2
D
C8H15ClO
Show answer
Answer: C. The ester is CH3COOC6H11: C 2 + 6 = 8, H 3 + 11 = 14, O 2. HCl is the other product, so no chlorine remains in the ester.
10. Phenol is dissolved in NaOH(aq) to give a clear solution. Excess dilute hydrochloric acid is then added. What is observed, and why?
A
the solution stays clear, because sodium phenoxide does not react with acid
B
bubbles of CO2 are given off from the phenoxide
C
a white precipitate of sodium chloride forms
D
the mixture turns cloudy, because phenoxide ions are protonated and the less soluble phenol separates
Show answer
Answer: D. Phenoxide is the conjugate base of a weak acid, so the strong acid converts it back to phenol, which is only slightly soluble and appears as a cloudy emulsion. NaCl is soluble, and no carbonate is present to give CO2.
50, each with the answer and a short explanation, across 2 topics: Alcohols, Phenol. Every chapter test draws ten of them, so you can take it many times.
Is the A Level Chemistry (A2) chapter 10 test free?
Yes. The test, the answers and the explanations are free and need no sign-up. Sign in only if you want your scores kept across devices.
How is the chapter test marked?
The moment you press Finish: your score, the right answer and an explanation for every question, and the ones you got wrong saved in My mistakes to retry.
