IGCSE Chemistry Paper-1: Specimen Questions with Answers 81 - 83 of 99

Question 81

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Question

MCQ▾

Which of this structure does not represent an allotropic form of carbon?

Which is not an allotrope of carbon

Which is Not an Allotrope of Carbon

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Choices

Choice (4)
a.A
b.C
c.B
d.D

Answer

d.

Explanation

In the above figures Fig A represents Diamond, fig B represents Graphite, Fig C represents fullerenes. Fig D represents coal which is not an allotropic form of carbon.

Question 82

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Question

MCQ▾

What is the chemical formula for plaster of paris?

Choices

Choice (4)
a.CaSO₄. 1/2H₂O
b.CaSO₄. 2H₂O
c.CaSO₄. H₂O
d.Question does not provide sufficient data or is vague

Answer

a.

Explanation

The chemical name of plaster of paris is Calcium sulphate hemi hydrate.

It is prepared by heating gypsum at 100 degree Celsius in rotary kilns, where it gets partially dehydrated.

Question 83

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Question

MCQ▾

Which of the following structure represents alcohol?

Choices

Choice (4)
a.
Correct structure for Alcohol – Choice A
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b.
Correct structure for Alcohol – Choice B
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c.Question does not provide sufficient data or is vague
d.None of the above

Answer

b.

Explanation

Alcohols are organic compounds consisting of hydroxyl group –OH attached to a carbon atom.

Choice B shows the structure of ethanol. Ethanol is the type of alcohol found in alcoholic drinks such as wine and beer. It is also useful as a fuel. For use in cars and other vehicles, it is usually mixed with petrol.

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