📖 Theory▼

Aim: To investigate the conditions required for rusting (oxygen + water).

Equation: 4Fe + 3O₂ + 6H₂O → 2Fe₂O₃·3H₂O (hydrated iron(III) oxide = rust)

Key Finding: Both water AND oxygen must be present for rusting. Either one alone does not cause rust.

⚠️ Safety▼

• Iron nails have sharp points — handle carefully to avoid pricks; a rusty nail can carry tetanus risk.

• Boiling water (to remove dissolved oxygen for Tube B) can scald — use tongs and let it cool before sealing.

• Anhydrous calcium chloride desiccant is an irritant and gets hot with moisture — do not touch with wet hands.

• The oil layer and salt water can stain — clean spills; wash hands after handling.

• Wear goggles; label the tubes clearly and keep them upright over the observation period.

Experiment Setup

4 test tubes with iron nails under different conditions. Click "Wait 7 Days" to see results.

Tube A: Water + Air (normal)
Tube B: Boiled water + Oil layer (no O₂)
Tube C: Dry air + Desiccant (no H₂O)
Tube D: Salt water + Air (accelerated)

🔮 Predict before you wait

Tick the tubes in which the nail will rust.

Tube A Water + Air Air ✓ Water ✓ Day 0 Tube B No Oxygen Oil layer No O₂ ✗ Water ✓ Day 0 Tube C No Water Air ✓ No H₂O ✗ CaCl₂ desiccant Day 0 Tube D Salt Water + Air Air ✓ Salt water ✓ Day 0 Day 0 — Setup complete
Observations
Click "Wait 7 Days" to see results...