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Which one of the following is the chemical formula of Plaster of Paris?

Options

  1. ACaSO ₄ 1 2 H ₂ O
  2. BCaSO ₄ 2 H ₂ O
  3. CCaSO ₄ 5 H ₂ O
  4. DCaSO ₄ 4 H ₂ O

Correct answer

A. CaSO ₄ 1 2 H ₂ O

Step-by-step solution

CaSO ₄ 1 / 2 H ₂ O . Calcium sulphate with half a molecule of water per molecule of salt (hemihydrate) is called plaster of Paris. It is prepared by heating gypsum ( CaSO ₄ 2 H ₂ O ) at 120^ C in rotary kilns, where it gets partially dehydrated.

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