CHEMISTRY · Stage 8 · Chapter 9: Chemical Reactions 2

Chemistry 9.10 Lead in the reactivity series — Environmental and Chemical Properties

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9.10 Lead in the reactivity series — Environmental and Chemical Properties — Alhussan International Academy — Chemistry (Stages 7–9) notes: Plan an investigation to place lead in the reactivity series and explain the uses and hazards of lead.Properties — lead is a dense, soft, gr…

X-ray aprons
Hazard symbols
Health effects
Unreactive but toxic
Risk assessment
Hypothesis

Section 1 of 6Properties and uses of lead

Properties
- lead is a dense, soft, grey metal.
X-ray aprons
- sheets of lead stop X-rays damaging internal organs, and lead also shields against gamma rays because it is dense.
Roofing
- lead is waterproof, easy to bend, resists weathering and lasts for more than a century.
Batteries
- lead and lead oxide react reversibly with sulfuric acid in rechargeable lead-acid car batteries that deliver a large current.

Section 2 of 6Hazards of lead

Hazard symbols
- a container of lead shows health and environmental hazards, because the element is poisonous and can be stored in the body.
Health effects
- lead builds up in the body and damages the nervous system, especially in children.
Past uses
- water pipes, paints and petrol additives, which have mostly been banned.
Environment
- used batteries must be recycled because lead can leak into soil and water.
- Recycling lead reduces mining, saves energy and prevents pollution.
Unreactive but toxic
- low reactivity does not mean safe, because toxicity is unrelated to position in the series.

Section 3 of 6Planning the investigation

Aim
- Deepa wants to find the position of lead in the reactivity series by studying its chemical properties.
Risk assessment
- because lead is poisonous she reduces the risk by not using it herself and gets evidence from secondary sources.
Evidence
- she watches a video of lead reacting with hydrochloric acid, where bubbles form more slowly than for zinc.
Hypothesis
- lead is between zinc and copper in the series because lead and acid bubble more slowly than zinc and acid, and copper does not react with acid.
Variables
- the independent variable is the metal, the dependent variable is how much it bubbles,
  - and the control variables are the acid concentration, size of metal pieces and acid temperature.

Section 4 of 6Carrying out and analysing

Experiments
- Deepa repeated the experiment in the lab with copper, iron and zinc, keeping the control variables as close as possible to the video.

Metal	Observation	Source
Lead	Steady bubbling	Internet (university chemistry department)
Copper	No reaction	Own experiment
Iron	Steady bubbling, faster than lead	Own experiment
Zinc	Fast bubbling	Own experiment

Conclusion
- the order of vigour is zinc, iron, lead, copper, so lead is between iron and copper in the reactivity series, supporting the hypothesis.
Limitations
- she does not know the size of the lead or the acid temperature in the video, so the test may not be fair, and bubbling is hard to compare.
Improvements
- react the metals with oxygen and with water too.
- If lead lies between iron and copper in those reactions as well, the conclusion is more certain.
Prediction for cold water
- lead would not react with cold water.

Section 5 of 6Chemical behaviour of lead

Position
- lead lies below iron and above copper, so it is of low to medium reactivity.
  - (just above hydrogen)
With acids
- it reacts very slowly, because an insoluble layer of lead chloride or lead sulfate coats the surface and protects it.
With water
- it does not react with cold water or steam.
With oxygen
- heated strongly in air, lead forms yellow lead oxide.
Displacement
- zinc displaces lead from lead nitrate solution as a feathery grey deposit, while lead displaces copper and silver from their solutions.
Extraction
- lead oxide is reduced by heating with carbon because lead is below carbon: lead oxide + carbon → lead + carbon dioxide.

Section 6 of 6Choosing materials

Weighing benefits and risks
- scientists and governments consider the evidence before changing rules and review limits as new studies appear.
Corrosion resistance
- lead is relatively unreactive, so its oxide layer protects it and it lasts outdoors.
Regulation
- evidence of harm led to lead-free modern paint, petrol and plumbing.
Alternatives
- less toxic metals such as zinc or copper also resist corrosion.

Last updated: 14 October 2026