Chemistry Aliphatic Hydrocarbons MCQs Chapter 8 Class 12 - PLS Academy

Chemistry Aliphatic Hydrocarbons MCQs – Chapter 8 Class 12

Chemistry Aliphatic Hydrocarbons is an important chapter of Class 12 Chemistry and plays a significant role in FSc Part-II exams and entry test preparation. MCQs from this chapter are frequently included in MDCAT, NUMS, AKU, NUST, UET ECAT, and board examinations. This chapter covers key topics such as classification of alkanes, alkenes, and alkynes, IUPAC nomenclature, physical and chemical properties, reactions, and industrial applications of aliphatic hydrocarbons.

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Created on February 10, 2022 By Ali Durrani

Chemistry Ch 8 Class 12 Hydrocarbons

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1 / 62

Which metal is used to form alkanes from alkyl halides?

Both a and b

None of these

2 / 62

Which of the following compounds will form a hydrocarbon on reaction with Grignard reagent?

PreMedPK MDCAT Mock 4
Chemistry
Hydrocarbons
Elimination Tool:

A) CH3CH2OH

B) CH3COOCH3

C) CH3COCH3

D) CH3CHO

3 / 62

) If 2-butene is treated with KMn04, the product is:

Butanoic acid

Propanoic acid

Butyric acid

Acetic acid

4 / 62

Which one of the following has the least C — C bond length?

Benzene

Ethane

Ethene

Ethyne

5 / 62

20 cm3 of a gaseous hydrocarbon was completely burnt in an excess of oxygen 60 cm3 of carbon dioxide and 40 cm3 of water vapours were formed, all volumes being measured at the same temperature and pressure. What is the formula of the hydrocarbon?

PreMedPK MDCAT Mock 5
Chemistry
Hydrocarbons
Elimination Tool:

A) C2H6

B) C3H4

C) C3H6

D) C3H8

6 / 62

Unsaturated Compound containing double bond is:

Alkane

Alkene

Alkyne

Alkylene

7 / 62

Electrophile in sulphonation of benzene is:

PMC 2020
Chemistry
Hydrocarbons
Elimination Tool:

A) HSO4-

B) H2SO4

C) SO3

D) HSO3

8 / 62

The electrophilic reactions of Benzene are:

PreMedPK MDCAT Mock 2
Chemistry
Hydrocarbons
Elimination Tool:

A) Halogenation

B) Nitration

C) Sulphonation

D) Alkylation and Acylation

E) All of these

9 / 62

CH ≡ CH + 2AgNO3 -> AgC ≡ CAg + 2HNO3 represents _____ property of acetylene.

NTS 2012
Chemistry
Hydrocarbons
Elimination Tool:

A) basic

B) acidic

C) dehydrating

D) physical

10 / 62

The electrophilic reactions of Benzene are:

NTS 2011
Chemistry
Hydrocarbons
Elimination Tool:

A) Halogenation

B) Nitration

C) Sulphonation

D) Alkylation and Acylation

E) All of these

11 / 62

Which one of the following is saturated hydrocarbon?

Octane

Nonane

Decane

All of the above

12 / 62

In Alkenes the Carbon atoms are connected to each other by a

Single bond

Double bond

Triple bond

Not connected

13 / 62

Which one of the following molecules has the shortest distance of carbon atoms?

PreMedPK MDCAT Mock 3
Chemistry
Hydrocarbons
Elimination Tool:

A) CH3- CH3

B) CH2= CH2

C) CH≡ CH

D) CH3- CH2- CH3

14 / 62

How many sigma groups are there in benzene?

NTS 2014
Chemistry
Hydrocarbons
Elimination Tool:

A) 3

B) 6

C) 9

D) 12

15 / 62

When CH3 is attached to the benzene ring, it makes the ring a:

PreMedPK MDCAT Mock 1
Chemistry
Hydrocarbons
Elimination Tool:

A) Good electrophile

B) Good nucleophile

C) Resonance hybrid

D) Extraordinary stable

16 / 62

Formula of Thionyl chloride is

SCI3

S2Cl2

SOCl2

SOCI3

17 / 62

Which of the following compounds react slower than benzene in electrophilic substitution reaction?

PreMedPK MDCAT Mock 5
Chemistry
Hydrocarbons
Elimination Tool:

A) Nitrobenzene

B) Phenol

C) Aniline

D) Toluene

18 / 62

Electrophile in sulphonation of benzene is:

PreMedPK MDCAT Mock 4
Chemistry
Hydrocarbons
Elimination Tool:

A) HSO4-

B) H2SO4

C) SO3

D) HSO3

19 / 62

Sp hybridization is found In which of the following?

Ethane

Ethene

Ethyne

None

20 / 62

Methane reacts with chlorine to form chloromethane. The catalyst used is?

NTS 2015 SMBBMC
Biology
Hydrocarbons
Elimination Tool:

A) Pb

B) Zn

C) HCl

D) Sunlight

21 / 62

The general formula of Methane Dichloride is:

CH3Cl2

CH4Cl2

CH2Cl2

None of these

22 / 62

Which of the following compounds possesses a single covalent bond between carbon and hydrogen?

NUMS 2016
Chemistry
Hydrocarbons
Elimination Tool:

A) CH4

B) C2H2

C) C2H4

D) All of the above

23 / 62

Which among the following gives ppt. with terminal alkynyl hydrogen?

PreMedPK MDCAT Mock 4
Hydrocarbons
Elimination Tool:

A) Ammonical silver nitrate

B) Ammoniacal cuprous chloride

C) Both a and b

D) None of these

24 / 62

Which type of isomerism depends on the distribution of carbon atoms on each side of the functional group?

PreMedPK MDCAT Mock 1
Chemistry
Hydrocarbons
Elimination Tool:

A) Structural isomerism

B) Functional isomerism

C) Chain isomerism

D) Metamerism

25 / 62

In alkanes all carbon atoms are linked by bond

Triple

Single

Double bonds

Alternative

26 / 62

Acetylene with Cl2 gives:

1, 2-dicholropropane

1, 1, 2, 2-tetrachloroethane

Ethane dichloride

1, 1, 2, 2-tetrachloromethene

27 / 62

Which one of the organic compounds Is the most reactive?

Alkane

Alkyne

Alkene

Nome

28 / 62

IUPAC Nomenclature of:

CH3 – CH = CH – CH2 – CH = CH2 is:

NTS 2011
Chemistry
Hydrocarbons
Elimination Tool:

A) 2 – pentene

B) 1 , 4 – hexadiene

C) 3 – methyl butane

D) 1, 3, 5 – heptatriene

29 / 62

In the reaction, R-C≡C-R → the reagent used to convert alkyne into trans alkene is:

NTS 2014
Chemistry
Hydrocarbons
Elimination Tool:

A) Ni

B) Lindlar catalyst

C) B2H6/CH3COOH

D) Li/NH3

30 / 62

When CH3 is attached to the benzene ring, it makes the ring a:

PMC 2020
Chemistry
Hydrocarbons
Elimination Tool:

A) Good electrophile

B) Good nucleophile

C) Resonance hybrid

D) Extraordinary stable

31 / 62

Physical properties of Ethyne is/are:

PreMedPK MDCAT Mock 3
Chemistry
Hydrocarbons
Elimination Tool:

A) It is colourless gas with a sweet smell.

B) It is sparingly soluble in water.

C) It is less dense than air.

D) It explodes on compression to a liquid because of unstable nature.

E) All of the above

32 / 62

Formula of propene is

C2H5

C3H6

C4H8

C6H6

33 / 62

KOLBE’s method is used to prepare?

Ethane

Ethene

Ethyne

All of these

34 / 62

How many chain isomers are shown by C5H12?

PreMedPK MDCAT Mock 4
Chemistry
Hydrocarbons
Elimination Tool:

A) 5

B) 4

C) 3

D) 2

35 / 62

Alkanes having five to seventeen carbon atoms per molecule are:

NTS 2013
Chemistry
Hydrocarbons
Elimination Tool:

A) liquids

B) solids

C) gases

D) semi solid wax

36 / 62

The major source of unburnt hydrocarbons in the atmosphere is / are:

NUMS 2016
Chemistry
Hydrocarbons
Elimination Tool:

A) Petroleum

B) Natural gas

C) Automobiles

D) Human beings

37 / 62

Generic formula of cycloalkane is:

PMC 2020
Chemistry
Hydrocarbons
Elimination Tool:

A) CnH2n+2

B) CnH2n

C) CnH2n – 1

D) CnH2n – 2

38 / 62

Which type of isomerism depends on the distribution of carbon atoms on each side of the functional group?

PreMedPK MDCAT Mock 1
Chemistry
Hydrocarbons
Elimination Tool:

A) Structural isomerism

B) Functional isomerism

C) Chain isomerism

D) Metamerism

39 / 62

Benzene in the presence of AlCl3 produces acetophenone when reacts with:

PreMedPK MDCAT Mock 4
Chemistry
Hydrocarbons
Elimination Tool:

A) Acetyl chloride

B) Acetic acid

C) Ethyl benzene

D) Ethanoic acid

40 / 62

Which type of isomerism depends on the distribution of carbon atoms on each side of the functional group?

NTS 2013
Chemistry
Hydrocarbons
Elimination Tool:

A) Structural isomerism

B) Functional isomerism

C) Chain isomerism

D) Metamerism

41 / 62

Percentage of butane in Sui gas is?

NTS 2015 SMBBMC
Biology
Hydrocarbons
Elimination Tool:

B) 3.88 %

C) 1.05 %

D) 0.02%

E) 0.17 %

42 / 62

Catenation is a process in which carbon shows the properties of:

NTS 2010
Chemistry
Hydrocarbons
Elimination Tool:

A) Making single bond

B) Hybridization

C) Making chains or rings of carbon atoms

D) Isomerism

43 / 62

NTS 2015 SMBBMC
Chemistry
Hydrocarbons
Elimination Tool:

A) C2H6

B) C3H4

C) C3H6

D) C3H8

44 / 62

H2 and Cl2 do not react in the dark, but in the presence of light a vigorous reaction is initiated due to the formation of:

NUMS 2016
Chemistry
Hydrocarbons
Elimination Tool:

A) Hydrogen free radical

B) Chlorine free radical

C) Hydrogen chloride molecule

D) Both hydrogen and chlorine free radicals

45 / 62

Which one of the following molecules has the shortest distance of carbon atoms?

NTS 2013
Chemistry
Hydrocarbons
Elimination Tool:

A) CH3- CH3

B) CH2= CH2

C) CH≡ CH

D) CH3- CH2- CH3

46 / 62

Boiling point of heptane is:

140

160

200

47 / 62

In which of the following cases are the benzene rings isolated?

PreMedPK MDCAT Mock 2
Chemistry
Hydrocarbons
Elimination Tool:

A) Naphthalene

B) Phenanthrene

C) Anthracene

D) Triphenylmethane

48 / 62

Which one of these is/are gasses?

Methane

Ethane

Propane

All of these

49 / 62

In which of the following C-C bond length is the minimum?

Alkane

Alkene

Benzene

Same length in all

50 / 62

When CH2 = CH2 reacts with a halogen acid, the product formed is:

Alkyl halide

Alkane

Alkyl

Allcene

51 / 62

The addition of HBr to an unsymmetrical alkenes follows?

PreMedPK MDCAT Mock 2
Chemistry
Hydrocarbons
Elimination Tool:

A) Direct addition

B) Markovnikov's addition

C) Anti Markovnikov's addition

D) Dehydration

52 / 62

Which step should be repeated over and over to get a variety of substituted products?

PreMedPK MDCAT Mock 5
Chemistry
Hydrocarbons
Elimination Tool:

A) None of these

B) Termination

C) Propagation

D) Initiation

53 / 62

1,4-dimethyl benzene is called as ______.

PreMedPK MDCAT Mock 5
Chemistry
Hydrocarbons
Elimination Tool:

A) Ortho-xylene

B) Para-xylene

C) Para-methyl toluene

D) Meta-methyl toluene

54 / 62

Benzene can be prepared from:

NTS 2011
Chemistry
Hydrocarbons
Elimination Tool:

A) From Petroleum

B) From Coal

C) From Acetylene

D) From Phenol

E) Al of these

55 / 62

The IUPAC name of the compound having structural formula CH3 — CH(OH) —COON is:

2-hydroxy propanoic acid

Lactic acid

a-hydroxy propanoic acid

Both a and b

56 / 62

Molecular Formula of Propane is:

C3H8

C4H10

C6H12

C7H14

57 / 62

What Is Lindlar Catalyst?

fe203 and Al2O3

AL1O1,SIO2, Cr2O3

Pd, CaCO, and Lead salts

Charcoal

58 / 62

Catalytic hydrogenation of alkenes exhibits:

PreMedPK MDCAT Mock 4
Chemistry
Hydrocarbons
Elimination Tool:

A) Substitution reaction

B) Elimination reaction

C) Addition reaction

D) Condensation reaction

59 / 62

Which of the following compounds possesses a single covalent bond between carbon and hydrogen?

PreMedPK MDCAT Mock 5
Chemistry
Hydrocarbons
Elimination Tool:

A) CH4

B) C2H2

C) C2H4

D) All of the above

60 / 62

Which gas among the following can be dried by bubbling in H2S04?

Ammonia gas

HCI gas

Ethyne

Oxygen gas

61 / 62

How many chain isomers are shown by C5H12?

NTS 2018
Chemistry
Hydrocarbons
Elimination Tool:

A) 5

B) 4

C) 3

D) 2

62 / 62

Benzene can be prepared from:

PreMedPK MDCAT Mock 2
Chemistry
Hydrocarbons
Elimination Tool:

A) From Petroleum

B) From Coal

C) From Acetylene

D) From Phenol

E) Al of these

Your score is

The average score is 67%

Importance of Aliphatic Hydrocarbons MCQs

A strong understanding of aliphatic hydrocarbons helps students predict reactions, identify compounds, and solve conceptual and numerical problems. Exams often include MCQs on reaction mechanisms, physical properties, and preparation methods of alkanes, alkenes, and alkynes. Practicing chapter-wise MCQs improves conceptual clarity, accuracy, and confidence for competitive exams.

Effective Strategy for Free Preparation

For effective preparation, students should revise nomenclature rules, reaction types, and properties of hydrocarbons regularly, and solve topic-wise MCQs consistently. Attempting free tests and past paper questions helps identify important concepts and repeated exam patterns. PLS Academy provides structured MCQs and free resources to support Chemistry Aliphatic Hydrocarbons preparation and other Class 12 Chemistry chapters.

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Comments

5 responses to “Chemistry Aliphatic Hydrocarbons MCQs Chapter 8 Class 12”

Sania batool

July 3, 2022

There is some answer problem, otherwise this is the best app which every medical student deserve.
1. Ali Durrani
  
  July 5, 2022
  
  can you please identify errors
Hasnain

September 21, 2022

Most reactive organic compound is alkene not alkynes
1. Anonymous
  
  March 19, 2023
  
  plzz correct the errors
Anonymous

March 31, 2023

How single covalent bond is present in alkenes and alkynes