Question 81 markMCQSection A

The chemical formula for plaster of Paris is:

Acids, Bases and Salts
Plaster of Paris

Options

(0)CaSO4⋅2H2O\mathrm{CaSO_4 \cdot 2H_2O}
(1)CaSO4⋅H2O\mathrm{CaSO_4 \cdot H_2O}
(2)CaSO4⋅12H2O\mathrm{CaSO_4 \cdot \frac{1}{2}H_2O}
(3)2CaSO4⋅H2O\mathrm{2CaSO_4 \cdot H_2O}

Official answer

The correct option is C.

Answer keywords:Plaster of Pariscalcium sulphate hemihydrateCaSO4.1/2H2O

Marking scheme

  1. 1.1 mark for selecting the correct option (C).

Hint

Plaster of Paris is a hemihydrate of calcium sulphate, meaning half a water molecule is associated with each formula unit of calcium sulphate.

Quick oral answer

The chemical formula of Plaster of Paris is CaSO4⋅12H2OCaSO_4 \cdot \frac{1}{2}H_2O.

Common mistakes

  1. 1.Confusing the formula of Plaster of Paris (CaSO4⋅12H2OCaSO_4 \cdot \frac{1}{2}H_2O) with Gypsum (CaSO4⋅2H2OCaSO_4 \cdot 2H_2O).

Analysis and explanation

Plaster of Paris is chemically known as calcium sulphate hemihydrate. Its chemical formula is CaSO4⋅12H2OCaSO_4 \cdot \frac{1}{2}H_2O.

  • Option A (CaSO4⋅2H2OCaSO_4 \cdot 2H_2O) represents Gypsum, which is the precursor heated to make Plaster of Paris.
  • Options B and D are incorrect chemical representations of the hemihydrate form.

Interesting facts

Plaster of Paris got its name because it was historically prepared by heating abundant deposits of gypsum found near Paris, France.

Question details

Q8 of 39 questions

Board
CBSE
Class
Class 10
Subject
Science
Year
2020
Section
Section A
Marks
1
Type
MCQ
Chapter
Acids, Bases and Salts
Topic
Plaster of Paris
Bloom's level
Remembering
Syllabus topic
Some important chemical compounds: Plaster of Paris

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Frequently asked questions

How many marks does this question carry in CBSE Class 10 Science 2020?

This question carries 1 mark in the CBSE Class 10 Science 2020 examination.

Which chapter does this question come from in Science?

This question is from the chapter "Acids, Bases and Salts" in the CBSE Class 10 Science syllabus.

What topic does this question cover in Science?

This question covers the topic "Plaster of Paris" from CBSE Class 10 Science.

What type of question is this in the CBSE Class 10 Science 2020 paper?

This is a MCQ question from Section A in the CBSE Class 10 Science 2020 paper.