Chemistry Aldehydes and Ketones MCQs Chapter 12 Class 12

Chemistry Aldehydes and Ketones MCQs – Chapter 12 Class 12

Chemistry Aldehydes and Ketones is an important chapter of Class 12 Chemistry and plays a key 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, nomenclature, structure, physical and chemical properties, and important reactions of aldehydes and ketones, including nucleophilic addition and oxidation reactions.

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Created on February 10, 2022 By Ali Durrani

Chemistry Ch 12 Class 12 Aldehydes and Ketones

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1 / 60

A student mixed ethyl alcohol with a small amount of sodium dichromate and added it to the hot solution of dilute sulphuric acid. A vigorous reaction took place. He distilled the product formed immediately. What was the product?

PreMedPK MDCAT Mock 3
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) Acetone

B) Acetic acid

C) Dimethyl ether

D) Acetaldehyde

2 / 60

Which of the following will not undergo aldol condensation?

PreMedPK MDCAT Mock 3
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) Acetaldehyde

B) Propanaldehyde

C) Benzaldehyde

D) Trideuteroacetaldehyde

3 / 60

What should be added to methane to produce HCN?

Ammonia

Nitrogen

Water

H+

4 / 60

Butanone on oxidation with K2Cr2O7 / H2SO4 forms:

NUMS 2020
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) Acetic acid

B) Acetic acid & Ethane

C) Methane & Propanoic acid

D) Propanoic acid & Methanoic acid

5 / 60

Q.2 Prokaryotic and eukaryotic cells generally have which of the following features in common?

A. Cell wall made of cellulose

B. Presence of linear chromosome

C. Presence of ribosomes

D. Presence of nucleus

6 / 60

Why is it necessary to distill aldehyde formed from oxidation of primary alcohol through acidified potassium dichromate (VI) solution or acidified sodium dichromate (VI) solution?

PreMedPK MDCAT Mock 5
Chemistry
Alcohols, Phenols and Ethers
Aldehydes and Ketones
Elimination Tool:

A) Aldehyde formed may be oxidized further to carboxylic acid concerned

B) Aldehyde formed is unstable and decompose back to original precursor i.e. primary alcohol

C) Aldehyde may be oxidised further to a ketone

D) Aldehyde formed may react with primary alcohol, the original reactant.

7 / 60

Cyanohydrins can be synthesized from ketones through:

PreMedPK MDCAT Mock 4
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) Nucleophilic addition reaction

B) Unimolecular Nucleophilic substitution reaction

C) Electrophilic substitution reaction

D) Bimolecular Nucleophilic substitution reaction

8 / 60

Ketones undergo reaction with which compound in the presence of acid to form oximes

Hydroxy methane

) Hydroxyl amine

Phenyl hydrazine

) None

9 / 60

H —CHO is:

Formaldehyde

Acetaldehyde

Ketone

Ester

10 / 60

Tincture of Iodine is:

NUMS 2015
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) In alcohol with CHI3

B) In alcohol with I2

C) In ethanol and water mixture with KI and I2

D) In KI and CH3I

11 / 60

Carbonyl group undergoes:

NUMS 2019 Reconduct
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) Electrophilic addition reaction

B) Nucleophilic addition reaction

C) Electrophilic substitution reaction

D) Nucleophilic substitution reaction

12 / 60

What one is the correct geometry of acetal?

PreMedPK MDCAT Mock 3
Aldehydes and Ketones
Elimination Tool:

A) Trigonal

B) Linear

C) Tetrahedral

D) Square planer

13 / 60

Which of the following represent the formula of Ketone?

R2C=O

RCHO

ROR

RCOOH

14 / 60

In Cannizzaro’s reaction, Benzyl alcohol is obtained from?

PreMedPK MDCAT Mock 4
Chemistry
Alcohols, Phenols and Ethers
Aldehydes and Ketones
Elimination Tool:

A) benzaldehyde

B) benzene

C) picric acid

D) benzyl chloride

15 / 60

Consider the following reaction:

R―CHO + 2[Ag(NH3)2]OH → R―COONH4 + 2Ag + 2NH3 + H2O This reaction represents one of the following tests.

PreMedPK MDCAT Mock 1
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) Fehling test

B) Benedict test

C) Ninhydrin test

D) Tollens test

16 / 60

What type of chemical reaction is this?
CH3CHO + NH3 -> CH3CH(OH)NH2

NUMS 2019 Cancelled
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) Addition – elimination

B) Electrophilic addition

C) Free radical addition

D) Nucleophilic addition

17 / 60

Treatment of propionaldehyde with Dil. the NaOH solution gives:

NUMS 2016
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) CH3 CH2COOCH2C2H5

B) CH3 CH2 CHOH CH2 CH2 CHO

C) CH3 CH2 CH (OH) CH(CH3) CHO

D) CH3 CH2 COCH2 CH2 CHO

18 / 60

In the addition of sodium bisulfite to carbonyl system, which of the following is a nucleophile?

PreMedPK MDCAT Mock 3
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) Sulphide ion

B) Sulfite ion

C) Hydride ion

D) Sodium ion

19 / 60

Odour of formaldehyde Is:

Pungent

Aromatic

c) Pleasant

Obnoxious

20 / 60

Which of the following can be oxidized to an aldehyde?

NUMS 2019 Cancelled
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) 2-Ethanoic acid

B) 2-Ethanoate

C) Diethyl ether

D) Ethanol

21 / 60

Identify the common name of the following compound:

CH₃CH₂COCH₂OH

PreMedPK MDCAT Mock 1
Chemistry
Aldehydes and Ketones
Fundamental Principles of Organic Chemistry
Elimination Tool:

A) Α-hydroxy-ethyl methyl aldehyde

B) Α-hydroxy-ethyl methyl ketone

C) Β-hydroxy-ethyl methyl ketone

D) Β-hydroxy-ethyl methyl ketone

22 / 60

Which of the following Compound is not reduced by NaBH4 ?

PreMedPK MDCAT Mock 1
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) Acetaldehyde

B) Acetone

C) Carboxylic acid

D) Alkene

23 / 60

Which of the following reactions is NOT shown by ketones?

NTS 2018
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) Reaction with HCN

B) Reaction with Fehling solution

C) Reaction with NaHSO3

D) Reaction with 2,4-dinitrophenyl-hydrazine

24 / 60

Ketone reacts with Grignard reagent to form ______ in acidic media?

NTS 2015 SMBBMC
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) Tertiary alcohol

B) isopropyl alcohol

C) primary alcohol

D) carboxylic acid

25 / 60

A diabetic person’s exhaled breath contains propanone. A student tries to test the diabetes by asking the person to bubble the reagent with his exhaled breath. Which of the following reagents would give a positive result?

PreMedPK MDCAT Mock 5
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) Aqueous Bromine

B) Fehling’s reagent

C) Tollen’s reagent

D) Alkaline aqueous iodine

26 / 60

In which of the following reaction alkyl ketones are converted Into carboxylic acid with one carbon atom less than the parent compound?

Haloform

Cannizzaro

Aldol

None

27 / 60

The general formula for an aldehyde is:

NTS 2010
Chemistry
Aldehydes and Ketones
Elimination Tool:

B) R-COOH

C) R-CO-R

D) R-X

E) R-CHO

28 / 60

Paraldehyde is formed by:

Formaldehyde

Acetaldehyde

Acetone

None of these

29 / 60

Oxidation of alcohol converts it into?

Aldehyde

Tertiary Alcohol

Alkane

Carboxylic Acid

30 / 60

NUMS 2019 Cancelled
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) Aqueous Bromine

B) Fehling’s reagent

C) Tollen’s reagent

D) Alkaline aqueous iodine

31 / 60

Ketone can be prepared by the oxidation of:

Primary alcohol

Secondary alcohol

Tertiary alcohol

None of these

32 / 60

Which of the following does not give iodoform test?

NUMS 2014
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) Ethanol

B) Ethanal

C) Acetophenone

D) Benzophenone

33 / 60

Simplest aromatic aldehyde has number of hydrogen atoms.

34 / 60

During oxidation of unsymmetrical ketones which atom is oxidized?

PreMedPK MDCAT Mock 5
Aldehydes and Ketones
PMC Practice 28
Elimination Tool:

A) Carbonyl carbon

B) Carbon attached to smaller number of hydrogen atom

C) Carbon attach to larger number of hydrogen atoms

D) Hydrogen

35 / 60

Aldehyde is prepared industrially by air oxidation of ethylene using catalyst

NaCN + HO

20% H2504 + 1% HgSO4

PdCl2 + CuCl2

K2Cr207 + H2504

36 / 60

Cyanohydrins can be synthesized from ketones through:

NUMS 2018
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) Nucleophilic addition reaction

B) Unimolecular Nucleophilic substitution reaction

C) Electrophilic substitution reaction

D) Bimolecular Nucleophilic substitution reaction

37 / 60

Which one of the following is used in making lozenges?

Methanol

Acetaldehyde

Acetone

Formaldehyde

38 / 60

Methyl ketones can be characterized by performing:

NUMS 2018
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) Iodoform test

B) Schiff’s test

C) Benedict’s reagent test

D) Tollen’s test

39 / 60

Phenylmethyl ketone can be converted into ethyl benzene in one step by using:

NUMS 2016
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) LiAlH4

B) Zn(Hg)-HCl

C) NaBH4

D) CH3MgI

40 / 60

Ketones and aldehydes are reduced in the presence of catalyst:

Al203

R-Mg-X

SOCl2

41 / 60

Why is water added after the reduction process of aldehyde and ketone with LiAlH4?

NUMS 2019 Cancelled
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) Because water reacts violently with LiAlH4

B) Because water will protonate LiAlH4

C) Because water inhibits the process

D) Because it will result to alkenes

42 / 60

Formaldehyde is Industrially Prepared from:

Methanol

Ethyl alcohol

Methyl alcohol

Oxidation of ethylene

43 / 60

Methyl Magnesium Bromide reacts with formaldehyde. The product will be:

Methyl Alcohol

Acetone

Ethyl Alcohol

Ethane

44 / 60

The flavour of amyl butyrate is:

PreMedPK MDCAT Mock 5
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) Mango

B) Raspberry

C) Apricot

D) Orange

45 / 60

Hybridization of carbon in -CHO group is:

NUMS 2019 Reconduct
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) sp

B) sp2

C) sp3

D) dsp

46 / 60

IUPAC Name of formaldehyde is

Ethanol

Methanal

c) Ethanol

Methyl alcohol

47 / 60

In which of the following reagent Cupric citrate complex is formed?

PreMedPK MDCAT Mock 5
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) Fehling's solution test

B) Benedict's solution test

C) Silver mirror test

D) sodium nitroprusside test

48 / 60

IUPAC name of propionaldehyde is:

Methanal

Acetaldehyde

Propanal

Butanal

49 / 60

Metaformaldehyde is a result of?

Condensation

Reduction

Polymerization

Oxidation

50 / 60

Phenylmethyl ketone can be converted into ethyl benzene in one step by using:

PreMedPK MDCAT Mock 2
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) LiAlH4

B) Zn(Hg)-HCl

C) NaBH4

D) CH3MgI

51 / 60

Identification tests for functional groups of organic compounds are associated with specific observations. Tollen’s reagent is an ammoniacal silver nitrate solution, which is used for the identification of a functional group X with an observation O. Identify X and O.

PreMedPK MDCAT Mock 2
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) X = Aldehyde O = Silver mirror

B) X = Ketone, O = grey precipitate

C) X = Ketone, O = Silver mirror

D) X = Aldehyde O = Red precipitate

52 / 60

Which of the following reagent is used to separate and purify carbonyl and non carbonyl compounds?

PreMedPK MDCAT Mock 3
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) HCN

B) BrMgCH3

C) NaHSO3

D) H2O

53 / 60

Meta-formaldehyde molecule has Oxygen MOMS:

One

Two

Three

Five

54 / 60

Which of the following reagent is used to separate and purify carbonyl and non carbonyl compounds?

PMC 2020
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) HCN

B) BrMgCH3

C) NaHSO3

D) H2O

55 / 60

Which class of the compounds is represented by the type formula ROR?

NUMS 2017
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) Esters

B) Ethers

C) Aldehydes

D) Ketones

56 / 60

Which of the following will not undergo aldol condensation?

NUMS 2016
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) Acetaldehyde

B) Propanaldehyde

C) Benzaldehyde

D) Trideuteroacetaldehyde

57 / 60

What is the color of the precipitate when Brady’s reagent is used to test a benzaldehyde?

NUMS 2019 Cancelled
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) Green

B) Brown

C) Magenta

D) Red

58 / 60

– ROR is the nucleophile of

NTS 2011
Chemistry
Aldehydes and Ketones
Elimination Tool:

A) Alcohols

B) Esters

C) Cyanides

D) Ethers

59 / 60

In Cannizzaro’s reaction out of two moles, one makes salt of an acid the other makes

Ester

Alcohol

Carboxylic Acid

Alkane

60 / 60

Tollen’s test is used for the detection of:

Aldehydes

Ketones

Carbonyl group

None of these

Your score is

The average score is 65%

Importance of Aldehydes and Ketones MCQs

A strong understanding of aldehydes and ketones helps students predict reactions, identify compounds, and solve conceptual and numerical problems. Exams often include MCQs on reaction mechanisms, functional group transformations, and comparative reactivity of aldehydes and ketones. 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 mechanisms, and properties of aldehydes and ketones 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 Aldehydes and Ketones preparation and other Class 12 Chemistry chapters.

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