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9701 A Level Chemistry/ Topic 32 Hydroxy compounds (A Level)/ 5 interactive simulations/ drag to rotate 3D scenes

Alcohols and phenol, made interactive

Five simulations covering Topic 32: ranking water, ethanol, phenol and ethanoic acid as O-H acids by pKa with the anion and its charge drawn, a sodium bench where bubble rate follows acidity and the NaOH and sodium carbonate tests separate phenol from carboxylic acids, esters made from ethanol with an acyl chloride and with a carboxylic acid with the alcohol oxygen traced, the delocalisation of the phenoxide charge into the ring in 3D, and the activated ring of phenol reacting with bromine water and dilute nitric acid where benzene does not.

1. Ranking the O-H acids 2D · 32.1

Water, ethanol and phenol all have an O-H bond, but they lose H⁺ with very different ease. The deciding factor is the anion left behind: if it is stable the acid is stronger. Pick each compound, look at where the negative charge sits, and compare the pKa values.

Compound

pKa
Ka / mol dm−3
pH of 0.100 mol dm−3
anion
COMPARED WITH ETHANOL
Exam point: a more stable anion means a stronger acid. Alkyl groups release electrons and destabilise RO⁻; delocalising the charge into a benzene ring stabilises C₆H₅O⁻. Phenol is made from chlorobenzene with NaOH(aq) at about 300 °C and high pressure, then acid, or industrially via cumene.

2. Sodium bench 2D · 32.1

The same four liquids, three different reagents. Sodium reacts with every O-H compound and gives hydrogen, faster the stronger the acid. Sodium hydroxide only reacts with phenol among the alcohols, and sodium carbonate only with the carboxylic acid. Choose a reagent, press Add, and read the observations.

Reagent

EQUATION (phenol)
CompoundObservation
Conditions: a small piece of dry sodium, or 1 cm³ of 1 mol dm−3 aqueous NaOH or Na₂CO₃. Bubble rates are drawn in proportion to acidity, and are illustrative. Only a carboxylic acid is acidic enough to liberate CO₂ from carbonate.

3. Ester two ways 3D · 32.1

Ethanol makes the same ester, ethyl ethanoate, from an acyl chloride or from a carboxylic acid. The acyl chloride is so reactive that the reaction is fast at room temperature; the acid needs a catalyst and heat and only reaches equilibrium. Step through each route and follow the gold ring: it marks the oxygen that came from the alcohol.

drag to rotate · wheel to zoom

Acylating agent

STEP
EQUATION
CONDITIONS
RATE AND EXTENT
Acyl chloride: add ethanol to ethanoyl chloride at room temperature, steamy fumes of HCl, no catalyst. Carboxylic acid: heat ethanol with ethanoic acid and a few drops of concentrated H₂SO₄, usually under reflux; reversible, so the ester is often distilled off.

4. Phenoxide in 3D 3D · 32.1

Why is phenol so much more acidic than ethanol? Take the proton away with NaOH and look at the phenoxide ion. The p orbital on oxygen carrying the lone pair points above and below the ring, in line with the ring's p orbitals, so the negative charge can spread onto carbons 2, 4 and 6. Drag to look along the ring.

drag to rotate · wheel to zoom

From phenol to phenoxide

STEP
EQUATION
NEGATIVE CHARGE ON
pKa OF THE ACID
Phenol + NaOH → sodium phenoxide + water, so phenol dissolves in alkali. Phenol + Na → sodium phenoxide + ½H₂. In ethoxide the electron-releasing ethyl group pushes charge onto O and destabilises the ion; in phenoxide the charge is delocalised, so phenol is about 106 times stronger an acid than ethanol.

5. Phenol's activated ring 2D · 32.2

An oxygen lone pair feeding into the ring makes phenol far more reactive towards electrophiles than benzene. Phenol decolourises bromine water at once with no catalyst and gives a white precipitate; benzene does nothing under the same conditions. Choose the compound and the reagent, then press Add.

Compound

Reagent

PRODUCT
CONDITIONS
Phenol + 3Br₂(aq) → 2,4,6-tribromophenol (white solid) + 3HBr. Phenol + dilute HNO₃ at room temperature gives 2-nitrophenol and 4-nitrophenol. Benzene needs a halogen carrier (FeBr₃) for bromination and concentrated HNO₃ with concentrated H₂SO₄ at about 50 °C for nitration.
TheLucidSTEM · Cambridge International A Level Chemistry 9701 · Topic 32 Hydroxy compounds (A Level). Every scene runs in the browser; drag to rotate 3D scenes, wheel to zoom. Values are standard textbook data rounded for teaching.

About this lab: Alcohols and phenol

Five interactive simulations for Cambridge A Level Chemistry 9701 topic 32 Hydroxy compounds: a pKa ladder for water, ethanol, phenol and ethanoic acid with the conjugate base drawn and the pH of a tenth-molar solution worked out, a sodium bench comparing hydrogen bubble rates and the sodium hydroxide and sodium carbonate tests, esterification of ethanol with ethanoyl chloride and with ethanoic acid stepped through in 3D with conditions and rate compared, the phenoxide ion in 3D with the oxygen p orbital overlapping the ring pi system, and the electrophilic substitution of phenol by bromine water and dilute nitric acid compared with benzene.

Five simulations covering Topic 32: ranking water, ethanol, phenol and ethanoic acid as O-H acids by pKa with the anion and its charge drawn, a sodium bench where bubble rate follows acidity and the NaOH and sodium carbonate tests separate phenol from carboxylic acids, esters made from ethanol with an acyl chloride and with a carboxylic acid with the alcohol oxygen traced, the delocalisation of the phenoxide charge into the ring in 3D, and the activated ring of phenol reacting with bromine water and dilute nitric acid where benzene does not.

Alcohols and phenol is a free, browser-based simulation for Cambridge International AS & A Level Chemistry 9701 (topic 32 Hydroxy compounds). The course is assessed in Paper 1 (Multiple Choice (AS)), Paper 2 (AS Structured), Paper 3 (Advanced Practical), Paper 4 (A Level Structured), Paper 5 (Planning, Analysis, Evaluation). Syllabus for examination in 2025-2027. There are 5 tabs, each a self-contained experiment with its own controls and live readings, and nothing to install: it runs on a laptop, tablet or classroom projector.

Syllabus coverage

Full syllabus map: A Level Chemistry 9701 topic 32.

How to use this simulation

  1. 1. Ranking the O-H acids. Water, ethanol and phenol all have an O-H bond, but they lose H⁺ with very different ease.
  2. 2. Sodium bench. The same four liquids, three different reagents.
  3. 3. Ester two ways. Ethanol makes the same ester, ethyl ethanoate, from an acyl chloride or from a carboxylic acid.
  4. 4. Phenoxide in 3D. Why is phenol so much more acidic than ethanol?
  5. 5. Phenol's activated ring. An oxygen lone pair feeding into the ring makes phenol far more reactive towards electrophiles than benzene.
  6. The buttons at the end of the tab strip give the scene the whole window (Full screen, Hide controls) and, on a dark stage, a projector-friendly palette (Light scene). Many scenes also have drag handles: drag them to change the set-up directly.

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