IGCSE Chemistry: Specimen Questions with Answers 25 - 28 of 240

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Question 25

Question

MCQ▾

Atomicity only appears for ________.

Choices

Choice (4)

a.

Elements

b.

Compounds

c.

Both a. and b. are correct

d.

Question does not provide sufficient data or is vague

Answer

c.

Explanation

  • The number of atoms of an element that join together to form a molecule of that element is known as atomicity of that molecule.
  • The smallest part of an element is atom. But the smallest part of a compound is molecule which exhibits all the chemical nature a compound shows.

Question 26

Edit

Write in Short

Short Answer▾

Malonic acid is a white crystalline solid which is soluble in water. It melts at 135 °C. The structural formula of malonic acid is given below. It forms salts called malonates

What is the molecular formula of malonic acid?

Explanation

Molecular formula of malonic acid is .

Question 27

Question

MCQ▾

Number of shells in potassium is ________.

Choices

Choice (4)

a.

1

b.

3

c.

4

d.

2

Answer

c.

Explanation

Correct Answer is D because it has atomic number . And electronic configuration and are in period so it has number of shell.

Question 28

Question

MCQ▾

________ acid is used in aerated drinks.

Choices

Choice (4)

a.

Sulphuric acid

b.

Acetic acid

c.

Hydrochloric acid

d.

Carbonic acid

Answer

d.

Explanation

Carbonic acid is used in aerated drinks.

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