Multiple choice

The main contituents of pearls are

  1. CO &CO2

  2. Calcium hydroxide & Water

  3. Sodium oxide & Oxygen

  4. Calcium carbonate & Magnesium carbonate
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Calcium carbonate and magnesium carbonate are correct. Pearls are primarily composed of calcium carbonate (CaCO3) in the form of aragonite crystals, held together by conchiolin (an organic protein). Natural pearls also contain small amounts of magnesium carbonate. The other options are incorrect - CO & CO2 are gases, calcium hydroxide is a different compound, and sodium oxide is not found in pearls.

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