# Chloroethane can undergo a substitution reaction with aqueous sodium hydroxide solution to form ethanol. Explain what happens during this reaction, including why chloroethane is reactive and what type of bond breaking occurs.

> Eduqas A-Level Chemistry — 2.6 Halogenoalkanes · Explain · 5 marks

> Chloroethane (CH₃CH₂Cl) reacts with aqueous sodium hydroxide solution. The product is ethanol (CH₃CH₂OH).

## Mark scheme (5 marks)

1. The C–Cl bond is polar (the chlorine atom is more electronegative than carbon)
2. The carbon bonded to chlorine carries a partial positive charge (δ+), making it susceptible to attack
3. The hydroxide ion (OH⁻) acts as a nucleophile
4. The C–Cl bond breaks heterolytically (both electrons go to the chlorine)
5. The chlorine leaves as a chloride ion (Cl⁻) and is replaced by the OH group, forming ethanol

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