🧪 Iron Reactivity with Acids
Iron (Fe) reacts with dilute acids-especially hydrochloric acid (HCl) and sulfuric acid (H₂SO₄)-to produce a salt and hydrogen gas (H₂). This is a typical redox reaction where iron is oxidized and hydrogen ions are reduced.
🔬 General Reaction:
Fe (s)+2HCl (aq)→FeCl2(aq)+H2(g)
or
Fe (s)+H2SO4→FeSO4+H2(g)
⚙️ Reaction Characteristics:
Bubbles of hydrogen gas are seen (effervescence).
The iron dissolves, forming iron salts like FeCl₂ or FeSO₄.
Reaction rate depends on:
Acid concentration
Surface area of iron
Temperature
❗ Reactivity Notes:
Iron reacts readily with dilute acids, but less violently than more reactive metals like zinc or magnesium.
With concentrated nitric acid (HNO₃), iron becomes passivated due to a protective oxide layer, and the reaction may stop.
⚡ Reactivity Series of Metals
| High Reactivity | Reacts vigorously with water and acids |
|---|---|
| Potassium (K) | 🔥 Very reactive |
| Sodium (Na) | 🔥 Very reactive |
| Calcium (Ca) | ⚠️ Reacts with cold water |
| Magnesium (Mg) | ⚡ Reacts with acids and warm water |
| Aluminum (Al) | ⚡ Reacts with acids (coated by oxide) |
| Zinc (Zn) | ✅ Reacts with dilute acids |
| Iron (Fe) | ✅ Reacts moderately with acids |
| Tin (Sn) | ⚠️ Slow reaction with acids |
| Lead (Pb) | ⚠️ Limited reaction with acids |
| Low Reactivity | Reacts only with strong oxidizers or not at all |
|---|---|
| Copper (Cu) | 🚫 No reaction with dilute acids (unless oxidizing) |
| Silver (Ag) | 🚫 Very unreactive |
| Gold (Au) | 🚫 Inert |
| Platinum (Pt) | 🚫 Inert |
🧲 Conclusion:
Iron reacts with most dilute acids to release hydrogen gas and form a salt, showing its moderate position in the reactivity series of metals.
