Chemistry 9th Chap 13 : Topic 7 - Maryam Publications

Chemistry Chapter 13 : Topic 7

Homologous Series Characteristics

1 / 15

Which statement best defines a homologous series in organic chemistry?

A) A mixture of organic compounds formed by random bonding of carbon atoms.

B) A group of compounds having identical molecular masses but different functional groups.

C) A set of compounds with different functional groups but same physical properties.

D) A group of organic compounds with same functional group and similar chemical properties, differing by - CH₂- units.

2 / 15

Which of the following is a key feature that ensures all members of a homologous series show similar chemical behavior?

A) Same physical state at room temperature

B) Same number of carbon atoms

C) Same functional group

D) Same molecular mass

3 / 15

A student observes that methane (CH₄), ethane (C₂H₆), and propane (C₃H₈) belong to the same group. What is the most valid reason?

A) They differ randomly in molecular structure.

B) They have the same number of hydrogen atoms.

C) They have identical boiling points.

D) Each successive compound differs by a - CH₂- unit.

4 / 15

Which general formula correctly represents a homologous series of alkanes?

A) CₙHₙ

B) CₙH₂ₙ

C) CₙH₂ₙ₋₂

D) CₙH₂ₙ₊₂

5 / 15

Which statement best explains why members of a homologous series show a gradual increase in boiling point?

A) Due to increase in intermolecular forces with increasing molecular size.

B) Due to change in functional group.

C) Due to random arrangement of atoms.

D) Due to decrease in molecular stability.

6 / 15

Why do all members of a homologous series show similar chemical reactions?

A) They have same structural formula.

B) They contain same number of atoms.

C) They have same physical state.

D) They contain the same functional group.

7 / 15

Which statement correctly describes the trend in physical properties in a homologous series?

A) They change irregularly without any pattern.

B) They show gradual change with increasing molecular mass.

C) They remain completely identical throughout the series.

D) They depend only on functional group, not size.

8 / 15

Which pair correctly represents consecutive members of a homologous series?

A) C₂H₆ and C₄H₁₀

B) CH₄ and CH₃OH

C) CH₄ and C₂H₆

D) C₃H₈ and C₃H₆

9 / 15

Which feature is NOT a characteristic of a homologous series?

A) Same functional group

B) Gradual change in physical properties

C) Same molecular mass

D) Same general formula

10 / 15

Why is the difference of - CH₂- important in a homologous series?

A) It creates a systematic increase in molecular size.

B) It makes compounds unrelated chemically.

C) It changes the functional group.

D) It keeps chemical properties completely different.

11 / 15

Which of the following best describes the relationship between ethane and propane in a homologous series?

A) They differ by one carbon and two hydrogen atoms (- CH₂- unit).

B) They are structural isomers.

C) They have identical molecular structures.

D) They have different functional groups.

12 / 15

What happens to the reactivity of members in a homologous series?

A) It becomes zero in higher members.

B) It depends only on physical state.

C) It changes completely with molecular size.

D) It remains similar due to same functional group.

13 / 15

Why do physical properties change gradually in a homologous series?

A) Due to random molecular arrangement

B) Due to increase in molecular size and mass

C) Due to change in functional group

D) Due to change in bonding type

14 / 15

Which statement correctly connects general formula and homologous series?

A) Each member has a completely different formula.

B) Formula depends on physical state.

C) Members follow a common general formula pattern.

D) Only first member follows a formula.

15 / 15

Which observation supports that a group of compounds belongs to a homologous series?

A) Each successive member differs by - CH₂- and shows similar reactions.

B) All have same molecular mass and structure.

C) All show completely different reactions.

D) All have identical boiling points.

Your score is

0%