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CAIE IGCSE Chemistry 9.5.3 Barrier methods prevent rusting by

CAIE IGCSE Chemistry 9.5.3 Barrier methods prevent rusting by
Cambridge IGCSE Chemistry 0620 syllabus for exams in 2026, 2027 and 20282026–2028

Practise explaining how complete coatings and rust-prevention experiments stop iron contacting oxygen or water.

How this is tested

  • explain painted, oily or plastic coatings by excluding oxygen and water from iron
  • interpret test-tube water levels to decide whether rusting has used up oxygen

Question 29

[Maximum number: 1]

An experiment to investigate the effect of painting iron is shown.

Figure for Question 29 — CAIE IGCSE Chemistry

The experiment is left for seven days.
What happens to the water level in test-tubes X and Y ?

test-tube X

test-tube Y

falls

rises

no change

no change

rises

falls

rises

no change