Phenol and ethanol are both members of the alcohol and phenol group of organic compounds. Describe the chemical properties of phenol, including its reactions with water and sodium hydroxide solution, and explain how these properties differ from those of ethanol.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (5 marks)
Phenol is only sparingly soluble in water, whereas ethanol is fully miscible with water.
When phenol dissolves in water it forms a weakly acidic solution because phenol can donate a proton from its hydroxyl group.
Ethanol, in contrast, does not donate a proton and its aqueous solution is neutral (or nearly neutral).
Phenol reacts with sodium hydroxide to give sodium phenoxide and water:
C6H5OH + NaOH → C6H5ONa + H2O
Ethanol does not react with sodium hydroxide under the same conditions.
When phenol dissolves in water it forms a weakly acidic solution because phenol can donate a proton from its hydroxyl group.
Ethanol, in contrast, does not donate a proton and its aqueous solution is neutral (or nearly neutral).
Phenol reacts with sodium hydroxide to give sodium phenoxide and water:
C6H5OH + NaOH → C6H5ONa + H2O
Ethanol does not react with sodium hydroxide under the same conditions.
Examiner tips
- Use the word ‘sparingly’ for phenol’s solubility, ‘fully miscible’ for ethanol. Mention the acidic nature of phenol’s aqueous solution and the neutral nature of ethanol’s. Write the balanced equation for phenol + NaOH. State that ethanol is unreactive with NaOH.
- common_mistakes
- :
- Saying phenol is ‘completely’ soluble in water. Forgetting to note that phenol’s solution is acidic. Writing the reaction with NaOH as phenol + NaOH → phenol + NaOH (no change).
Mark scheme (5 marks)
- Phenol is only slightly/sparingly soluble in water (or dissolves to a limited extent), whereas ethanol is fully miscible with water
- Phenol dissolved in water produces an acidic solution (phenol is a weak acid)
- Ethanol does not produce an acidic solution / ethanol solution is neutral (or near-neutral)
- Phenol reacts with sodium hydroxide solution to form sodium phenoxide (and water)
- Ethanol does not react with sodium hydroxide solution (unlike phenol)
Key terms in this question
Related
- All Eduqas A-Level Chemistry revision notes →
- How to answer a "Describe" question →
- Decode the mark scheme abbreviations →
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