Sodium reacts with water to produce sodium hydroxide and hydrogen gas. Explain why it is important to check the hazard symbols on the chemical containers before carrying out this reaction, and describe one safety precaution a student should take when handling sodium.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Sodium is a highly reactive metal that must be stored under oil to prevent it from reacting with moisture in the air. When a small piece of sodium is placed in water, it reacts vigorously.
Model answer (4 marks)
Hazard symbols show that sodium is corrosive and reacts violently with water, so the user knows the risks before handling it.
This information lets the student choose the right precautions and avoid injury.
Sodium is highly reactive with water, producing heat and hydrogen gas.
A safety precaution is to use forceps or tongs and wear safety goggles while handling a small piece of sodium, keeping it away from water until ready to react.
This information lets the student choose the right precautions and avoid injury.
Sodium is highly reactive with water, producing heat and hydrogen gas.
A safety precaution is to use forceps or tongs and wear safety goggles while handling a small piece of sodium, keeping it away from water until ready to react.
Examiner tips
- Use the exact hazard terms (corrosive, flammable, reacts violently).
- Show the link between hazard symbols and choosing precautions.
- Give a specific precaution that matches the hazard (forceps, goggles, small quantity).
Common mistakes
- Writing ‘sodium is toxic’ instead of the correct hazard.
- Omitting the link between hazard symbols and safety choices.
Mark scheme (4 marks)
- Hazard symbols communicate the dangers/hazards associated with a chemical so that the user knows the risks before handling it
- This allows appropriate safety precautions to be chosen / prevents injury or accident
- Sodium is corrosive / flammable / harmful / reacts violently with water (any one correct hazard property of sodium)
- A correct safety precaution when handling sodium, e.g. use forceps/tongs (not bare hands), wear safety goggles, wear gloves, use only a small piece of sodium, keep away from water until ready
Key terms in this question
hazard symbol · safety precaution
Related
- All Edexcel GCSE Chemistry (1CH0) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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