Acid Rain vs Marble

Why it matters

Acid rain is not just water; it is a slow-acting chemical eraser that dissolves the calcium carbonate in marble statues and monuments.

The idea in plain words

Map the atoms: CaCO₃ + H₂SO₄ → CaSO₄ + CO₂ + H₂O. Notice how the carbonate group breaks apart.

Predict first

What happens when acid rain (containing H₂SO₄) hits a marble building?

Marble is calcium carbonate. Acids react with carbonates to produce salt, water, and carbon dioxide gas, physically breaking down the stone structure.

• The marble dissolves, releasing gas and forming a new salt — correct
• The marble becomes harder and shinier
• Nothing happens because marble is rock
• The acid evaporates instantly

What you do

Add the acid to the marble chips. Observe the effervescence — and notice the fizzing slow down as a white crust of CaSO₄ forms on the marble, shielding it. That slow surface attack is exactly how acid rain eats monuments.

Check yourself

Which gas is released during this reaction?

Carbonates react with acids to release CO₂ gas, seen as effervescence.

Why does acid rain damage the Taj Mahal?

The Taj Mahal is made of marble (CaCO₃). Acid rain reacts with the calcium carbonate to form calcium sulphate (CaSO₄) and other products, eroding the surface.

What is the solid product formed in the reaction CaCO₃ + H₂SO₄?

The double decomposition reaction produces calcium sulphate (CaSO₄), water, and carbon dioxide.

• Oxygen (O₂)
• Carbon dioxide (CO₂) — correct
• Hydrogen (H₂)
• Sulphur dioxide (SO₂)
• The acid reacts with calcium carbonate in the marble — correct
• The acid melts the marble like ice
• The acid stains the marble yellow
• The acid makes the marble magnetic
• Calcium oxide (CaO)
• Calcium sulphate (CaSO₄) — correct
• Calcium chloride (CaCl₂)
• Unreacted Calcium carbonate