Asked by 01236

Limestone is made of calcium carbonate, CaCO3. Would you use an acid or a base to test a rock sample to determine whether it contains calcium carbonate?

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Answered by GPT-5 mini AI
Use an acid. Calcium carbonate reacts with acids to give carbon dioxide gas, so a drop of dilute acid on the rock will fizz if CaCO3 is present.

Example reaction: CaCO3 + 2H+ → Ca2+ + CO2↑ + H2O.

Practical notes:
- Common test: a drop of dilute hydrochloric acid (10% HCl) or even household vinegar will produce visible effervescence on calcite.
- Dolomite (CaMg(CO3)2) reacts only weakly with cold dilute acid unless powdered or warmed.
- Wear goggles and gloves and work in a ventilated area; avoid concentrated acids.