Most Important Carboxylic Acid Quiz Test Online

Carboxylic Acid Quiz Test Online

Carboxylic Acid Test. 1

1 / 20

1) How many carboxyl groups are present in a tricarboxylic acid?

Three

Four

Two

One

Carboxylic acids are classified based on the number of carboxyl groups; 'tri' indicates three.

2 / 20

2) What is the common name for CH₃CH₂CH₂COOH?

Butyric acid

Propionic acid

Acetic acid

Valeric acid

CH₃CH₂CH₂COOH is commonly known as Butyric acid.

3 / 20

3) The carboxyl group is a combination of which two groups?

Hydroxyl and aldehyde

Carbonyl and alkyl

Carbonyl and ether

Carbonyl and hydroxyl

The carboxyl group is made up of a carbonyl group (>C=O) and a hydroxyl group (-OH).

4 / 20

4) What type of carboxylic acid is benzoic acid?

Aliphatic dicarboxylic acid

Aliphatic monocarboxylic acid

Aromatic monocarboxylic acid

Aromatic dicarboxylic acid

Benzoic acid is an aromatic monocarboxylic acid due to the benzene ring.

5 / 20

5) Why are the first four members of aliphatic acids very soluble in water?

Due to hydrogen bonding

Due to ionic character

Due to van der Waals forces

Due to their small size only

Hydrogen bonding with water molecules makes them highly soluble.

6 / 20

6) What is the smell characteristic of the first three aliphatic acids (formic, acetic, propionic acid)?

Pleasant and fruity

Sweet

Odorless

Pungent

They are colorless liquids with a characteristic pungent odor.

7 / 20

7) What is the IUPAC name for formic acid?

Methanoic acid

Ethanoic acid

Propanoic acid

Butanoic acid

Formic acid is also known as Methanoic acid in IUPAC nomenclature.

8 / 20

8) How many carbon atoms does the carboxylic acid produced from an alkyl halide via alkanenitrile hydrolysis have, compared to the original alkyl halide?

The same number of carbon atoms

One carbon atom more

Two carbon atoms more

One less carbon atom

Cyanide adds one carbon atom during the reaction, increasing the chain length.

9 / 20

9) The hydrolysis of esters to form carboxylic acids is typically done by boiling with:

Conc. sodium hydroxide

Acetic acid

Aqueous ethanol

Dilute HCl

This forms a salt which on acidification gives carboxylic acid.

10 / 20

10) The hydrolysis of alkanenitriles to carboxylic acids requires boiling with:

Water only

Strong bases only

Organic solvents

Mineral acids or alkalis

Boiling with mineral acids or alkalis hydrolyzes nitriles to carboxylic acids.

11 / 20

11) Which of the following functional groups defines a carboxylic acid?

-OH

-COOR

-COOH

-CHO

The functional group for carboxylic acids is the carboxyl group, which is written as -COOH.

12 / 20

12) The IUPAC names of saturated monocarboxylic acids are derived from alkanes by changing the ending 'e' to:

-ol

-oic acid

-al

-one

The IUPAC names of saturated monocarboxylic acids are alkanoic acids, ending with -oic acid.

13 / 20

13) Symmetrical alkenes when heated with alkaline KMnO₄ are cleaved at the double bond to form:

Alcohols

Carboxylic acids

Ketones

Ethers

Alkaline KMnO₄ cleaves double bonds oxidatively to yield carboxylic acids.

14 / 20

14) Acetic acid was first isolated from which source?

Butter

Ants

Vinegar

Fats and oils

Acetic acid was first isolated from vinegar.

15 / 20

15) Carboxylic acids have relatively high boiling points due to:

Intermolecular hydrogen bonding

Covalent bonding

London dispersion forces

Strong dipole-dipole interactions

Hydrogen bonding between carboxylic acid molecules leads to higher boiling points.

16 / 20

16) In the preparation of carboxylic acids from Grignard reagents, the addition product is reacted with:

A mineral acid

An organic base

An alkali

An alcohol

The addition product is acidified with a mineral acid to yield the acid.

17 / 20

17) Which of the following is the general formula for an aliphatic carboxylic acid?

R-OH

R-C-OH (where R = H or an alkyl group)

Ar-C-OH

R-CHO

The general formula is R-COOH or R-C(=O)OH, where R is H or an alkyl group.

18 / 20

18) Primary alcohols and aldehydes can be oxidized to carboxylic acids using which of the following reagents?

LiAlH₄ in an acidic medium

H₂/Ni in an acidic medium

K₂Cr₂O₇ in an acidic medium

NaBH₄ in an acidic medium

Potassium dichromate in acidic medium is a strong oxidizing agent for this purpose.

19 / 20

19) Which of the following is an example of an aliphatic dicarboxylic acid?

Oxalic acid

Acetic acid

Benzoic acid

Formic acid

Oxalic acid (Ethanedioic acid) is an example of an aliphatic dicarboxylic acid.

20 / 20

20) Carboxylic acids can be prepared from Grignard reagents by reacting them with:

Alcohols

Carbon dioxide

Aldehydes

Water

Grignard reagents react with CO₂ followed by acidification to form carboxylic acids.

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Carboxylic Acid Test. 2

1 / 20

1) What are ammonium salts formed when carboxylic acids react with ammonia?

Acid amides

Carboxylic acids

Esters

Acid anhydrides

Carboxylic acids react with ammonia to form ammonium salts which on heating produce acid amides.

2 / 20

2) Heating carboxylic acids with alcohols in the presence of concentrated H₂SO₄ leads to the formation of:

Ketones

Aldehydes

Esters

Ethers

When carboxylic acids are heated with alcohols in the presence of concentrated H₂SO₄, esters are formed.

3 / 20

3) When dissolved in water, carboxylic acids furnish which ion?

H⁺

R⁻

OH⁻

CO₃²⁻

They furnish H⁺ when dissolved in water.

4 / 20

4) In most reactions of carboxylic acids, which part of the molecule is typically retained?

The carboxyl group

The carbonyl group

The hydroxyl group

The alkyl group

In most reactions of carboxylic acids, the carboxyl group is retained.

5 / 20

5) What type of reaction occurs when a nucleophile attacks the carboxyl group, followed by the displacement of the -OH group?

Elimination reaction

Nucleophilic addition followed by substitution

Addition reaction

Oxidation reaction

The addition of a nucleophile to the carboxyl group is always followed by the displacement of the -OH group by some other group, producing a carboxylic acid derivative.

6 / 20

6) The reaction of acetic acid with sodium carbonate produces sodium acetate, water, and:

Methane

Carbon dioxide

Carbon monoxide

Hydrogen

2CH₃COOH + Na₂CO₃ → 2CH₃COONa + CO₂ + H₂O

7 / 20

7) The reaction of CH₃COOH with PCl₅ produces CH₃COCl, POCl₃, and:

H₂O

Cl₂

SO₂

HCl

CH₃COOH + PCl₅ → CH₃COCl + POCl₃ + HCl

8 / 20

8) Which of the following is a laboratory method for preparing acetic acid?

Oxidation of methane

Fermentation of glucose directly

Oxidation of ethyl alcohol

Reduction of methyl cyanide

Ethyl alcohol is oxidized to acetic acid in laboratory synthesis.

9 / 20

9) Carboxylic acids are considered weaker acids compared to:

Alcohols

Water

Mineral acids

Phenols

Carboxylic acids are weaker acids than mineral acids.

10 / 20

10) What is the melting point trend observed for carboxylic acids with an even number of carbon atoms compared to their odd-numbered counterparts?

Their melting points are similar.

They have higher melting points.

There is no observable trend.

They have lower melting points.

Even-numbered acids pack more efficiently in solids, leading to higher melting points.

11 / 20

11) What is formed when carboxylic acids react with bases like NaOH or KOH?

Salts

Aldehydes

Esters

Ethers

Carboxylic acids react with bases (NaOH, KOH) to form salts.

12 / 20

12) In non-polar solvents like benzene, carboxylic acids exist as:

Monomers

Open-chain trimers

Polymers

Cyclic dimers

In non-polar solvents, two acid molecules dimerize through hydrogen bonding.

13 / 20

13) When carboxylic acids react with active metals (Na, K, Ca, Mg), what is evolved along with the formation of their salts?

Hydrogen gas

Carbon dioxide gas

Nitrogen gas

Oxygen gas

Carboxylic acids react with active metals (Na, K, Ca, Mg etc.) to form their salts with the evolution of hydrogen gas.

14 / 20

14) The reactivity of carboxylic acid molecules is primarily a consequence of the presence of which group?

Alkyl group

Carbonyl group

Carboxyl group as a whole

Hydroxyl group

The reactivity of these molecules is a consequence of the presence of the carbonyl group.

15 / 20

15) The -OH group of carboxylic acids can be replaced by which of the following to form acid derivatives?

O and N

Only halogen atoms

H and CH₃

X, OR and NH₂

The -OH group can thus be replaced by X, OR and NH₂ to form halides, esters and amides, respectively.

16 / 20

16) The hydrolysis of ethanenitrile to acetic acid proceeds through which intermediate?

Ethyl acetate

Acetaldehyde

Acetic anhydride

Acetamide

The intermediate formed is acetamide, which hydrolyzes to acetic acid.

17 / 20

17) What is the characteristic smell of esters, often leading to their use as artificial flavors?

Pungent

Unpleasant

Fruity

Sour

Esters have a fruity smell and are used as artificial flavors.

18 / 20

18) Which gas is evolved when carboxylic acids decompose carbonates and bicarbonates?

Methane gas

Oxygen gas

Hydrogen gas

Carbon dioxide gas

Carboxylic acids decompose carbonates and bicarbonates evolving carbon dioxide gas with effervescence.

19 / 20

19) What is 'glacial acetic acid' characterized by?

Its ability to freeze into an ice-like solid at 17 °C.

Its strong pungent smell.

Its immiscibility with water.

Its very low boiling point.

Pure acetic acid solidifies at 17 °C, resembling ice — hence the term 'glacial'.

20 / 20

20) Which of the following statements about the carboxyl group's reactivity is true?

It displays the chemistry of both the carbonyl and the hydroxyl groups.

It only displays the chemistry of the hydroxyl group.

It has no specific reactivity due to its stable nature.

It only displays the chemistry of the carbonyl group.

The carboxyl group displays the chemistry of both the carbonyl and the hydroxyl groups.

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Carboxylic Acid Test. 3

1 / 20

1) What are carboxylic acids completely reduced to when reacted with HI and red phosphorus?

Alkanes

Aldehydes

Alkenes

Alkynes

Carboxylic acids on reduction with HI and red phosphorus give alkanes.

2 / 20

2) What is the product when ammonium acetate (CH₃COONH₄) is heated?

Acetic acid + Ammonia

Acetamide + Water

Acetic anhydride + Water

Ethyl acetate + Water

Ammonium salts formed by the reaction of carboxylic acids with ammonia produce acid amides upon heating (CH₃COONH₄ → CH₃CONH₂ + H₂O).

3 / 20

3) What is the product formed when carboxylic acids react with NH₃ and are subsequently heated?

Acid anhydride

Acid amide

Alkyl nitrile

Ammonium salt only

Carboxylic acids react with ammonia to form ammonium salts which on heating produce acid amides.

4 / 20

4) Which of the following is a key step in the mechanism of ester formation from carboxylic acids and alcohols?

Elimination of an alkane

Deprotonation of the carboxylic acid

Formation of a ketone intermediate

Protonation of the carboxylic acid

The first step in the mechanism of ester formation (esterification) is the protonation of the carboxylic acid.

5 / 20

5) The formation of an ester from a carboxylic acid and an alcohol in the presence of concentrated H₂SO₄ is known as:

Saponification

Amidation

Hydrolysis

Esterification

When carboxylic acids are heated with alcohols in the presence of concentrated H₂SO₄, esters are formed.

6 / 20

6) What is the product of the partial reduction of carboxylic acids with lithium aluminum hydride (LiAlH₄)?

Aldehydes

Alcohols

Alkanes

Ethers

Carboxylic acids on reaction with lithium aluminum hydride (LiAlH₄) are reduced to alcohols.

7 / 20

7) Which reagent is used to convert carboxylic acids into acyl chlorides, along with SO₂ and HCl as by-products?

SCl₂

Cl₂

SOCl₂

PCl₅

Carboxylic acids react with SOCl₂ to form acyl chlorides, SO₂, and HCl.

8 / 20

8) The dehydration of carboxylic acids using phosphorus pentoxide (P₂O₅) on strong heating leads to the formation of:

Acid anhydrides

Esters

Acid amides

Acyl halides

Carboxylic acids are dehydrated on heating strongly in the presence of phosphorus pentoxide to form acid anhydrides.

9 / 20

9) What happens to the -OH group of a carboxylic acid when it forms a derivative like an acyl halide, ester, or amide?

It remains unchanged.

It is reduced to a hydrogen atom.

It is oxidized to a carbonyl group.

It is replaced by another group.

The addition of a nucleophile to the carboxyl group is always followed by the displacement of the -OH group by some other group, producing a carboxylic acid derivative.

10 / 20

10) What is the product of the reaction between ethanoic acid (CH₃COOH) and ethanol (C₂H₅OH) in the presence of H₂SO₄?

Acetamide

Ethyl alcohol

Ethanoic anhydride

Ethyl acetate

CH₃COOH + C₂H₅OH → CH₃COOC₂H₅ + H₂O.

11 / 20

11) Which of the following is true regarding the reactivity of carboxylic acids based on the carbonyl group?

The carbonyl group only affects physical properties, not reactivity.

The reactivity is a consequence of the presence of the carbonyl group.

The carbonyl group decreases the reactivity.

The carbonyl group has no influence on reactivity.

The reactivity of these molecules is a consequence of the presence of the carbonyl group.

12 / 20

12) The overall process by which carboxylic acids react with alcohols to form esters and water is known as:

Esterification

Dehydration

Hydrolysis

Saponification

The formation of an ester when carboxylic acids are heated with alcohols in the presence of concentrated H₂SO₄ is known as esterification.

13 / 20

13) Which reagent is used to dehydrate carboxylic acids on strong heating to form acid anhydrides?

Concentrated H₂SO₄

Lithium aluminum hydride (LiAlH₄)

Potassium permanganate (KMnO₄)

Phosphorus pentoxide (P₂O₅)

Carboxylic acids are dehydrated on heating strongly in the presence of phosphorus pentoxide.

14 / 20

14) What type of functional group is formed when the -OH group of a carboxylic acid is replaced by −NH₂?

Anhydride

Acyl halide

Amide

Ester

The -OH group can be replaced by X, OR, and NH₂ to form halides, esters, and amides, respectively.

15 / 20

15) Which of the following is a common step in the mechanism of forming acyl chlorides from carboxylic acids using SOCl₂?

Formation of a sulfinyl chloride intermediate

Addition of water

Protonation of the alkyl group

Reduction of the carbonyl group

The mechanism for the reaction of CH₃COOH with SOCl₂ shows the formation of an intermediate where sulfur is bonded to the carboxyl oxygen and a chlorine atom.

16 / 20

16) What is the product when acetic acid (CH₃COOH) reacts with PCl₅?

Acetyl chloride (CH₃COCl)

Ethyl acetate

Acetic anhydride

Acetamide

The reaction of CH₃COOH with PCl₅ yields CH₃COCl (Acetyl chloride), POCl₃, and HCl.

17 / 20

17) What happens to the proton (H⁺) in the presence of water (H₂O) when a carboxylic acid dissociates?

It remains as H⁺

It breaks away as H₃O⁺ ion

It combines with the solvent to form an insoluble precipitate

It forms a covalent bond with the carboxylate ion

In the presence of water (H₂O), the proton breaks away as H₃O⁺ ion.

18 / 20

18) Which of the following is NOT a common carboxylic acid derivative discussed in the text?

Amides

Ethers

Acyl halides

Esters

The -OH group can be replaced by X, OR and NH₂ to form halides, esters and amides, respectively.

19 / 20

19) When CH₃COOH reacts with SOCl₂, what are the products?

CH₃COOS + H₂O

CH₃COCl + SO₂ + HCl

CH₃COCl + H₂O

CH₃COCl + SO₃ + HCl

The reaction of CH₃COOH with SOCl₂ produces acetyl chloride (CH₃COCl), sulfur dioxide (SO₂), and hydrochloric acid (HCl).

20 / 20

20) Which of the following compounds has a fruity smell and is used as an artificial flavor?

Aldehyde

Carboxylic acid

Ester

Amide

Esters have a fruity smell and are used as artificial flavours.

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Carboxylic Acid Test. 3

1 / 20

1) The dehydration of carboxylic acids using phosphorus pentoxide (P₂O₅) on strong heating leads to the formation of:

Esters

Acid amides

Acid anhydrides

Acyl halides

Carboxylic acids are dehydrated on heating strongly in the presence of phosphorus pentoxide to form acid anhydrides.

2 / 20

2) Which reagent is used to convert carboxylic acids into acyl chlorides, along with SO₂ and HCl as by-products?

SOCl₂

SCl₂

PCl₅

Cl₂

Carboxylic acids react with SOCl₂ to form acyl chlorides, SO₂, and HCl.

3 / 20

3) When CH₃COOH reacts with SOCl₂, what are the products?

CH₃COCl + SO₃ + HCl

CH₃COCl + SO₂ + HCl

CH₃COCl + H₂O

CH₃COOS + H₂O

The reaction of CH₃COOH with SOCl₂ produces acetyl chloride (CH₃COCl), sulfur dioxide (SO₂), and hydrochloric acid (HCl).

4 / 20

4) What is the product when acetic acid (CH₃COOH) reacts with PCl₅?

Acetamide

Ethyl acetate

Acetic anhydride

Acetyl chloride (CH₃COCl)

The reaction of CH₃COOH with PCl₅ yields CH₃COCl (Acetyl chloride), POCl₃, and HCl.

5 / 20

5) The overall process by which carboxylic acids react with alcohols to form esters and water is known as:

Saponification

Hydrolysis

Dehydration

Esterification

The formation of an ester when carboxylic acids are heated with alcohols in the presence of concentrated H₂SO₄ is known as esterification.

6 / 20

6) What is the product of the reaction between ethanoic acid (CH₃COOH) and ethanol (C₂H₅OH) in the presence of H₂SO₄?

Ethanoic anhydride

Ethyl acetate

Acetamide

Ethyl alcohol

CH₃COOH + C₂H₅OH → CH₃COOC₂H₅ + H₂O.

7 / 20

7) What happens to the -OH group of a carboxylic acid when it forms a derivative like an acyl halide, ester, or amide?

It is replaced by another group.

It is reduced to a hydrogen atom.

It is oxidized to a carbonyl group.

It remains unchanged.

The addition of a nucleophile to the carboxyl group is always followed by the displacement of the -OH group by some other group, producing a carboxylic acid derivative.

8 / 20

8) Which reagent is used to dehydrate carboxylic acids on strong heating to form acid anhydrides?

Concentrated H₂SO₄

Phosphorus pentoxide (P₂O₅)

Lithium aluminum hydride (LiAlH₄)

Potassium permanganate (KMnO₄)

Carboxylic acids are dehydrated on heating strongly in the presence of phosphorus pentoxide.

9 / 20

9) What happens to the proton (H⁺) in the presence of water (H₂O) when a carboxylic acid dissociates?

It remains as H⁺

It combines with the solvent to form an insoluble precipitate

It forms a covalent bond with the carboxylate ion

It breaks away as H₃O⁺ ion

In the presence of water (H₂O), the proton breaks away as H₃O⁺ ion.

10 / 20

10) Which of the following is NOT a common carboxylic acid derivative discussed in the text?

Esters

Ethers

Amides

Acyl halides

The -OH group can be replaced by X, OR and NH₂ to form halides, esters and amides, respectively.

11 / 20

11) Which of the following is true regarding the reactivity of carboxylic acids based on the carbonyl group?

The reactivity is a consequence of the presence of the carbonyl group.

The carbonyl group decreases the reactivity.

The carbonyl group only affects physical properties, not reactivity.

The carbonyl group has no influence on reactivity.

The reactivity of these molecules is a consequence of the presence of the carbonyl group.

12 / 20

12) Which of the following compounds has a fruity smell and is used as an artificial flavor?

Aldehyde

Ester

Amide

Carboxylic acid

Esters have a fruity smell and are used as artificial flavours.

13 / 20

13) What type of functional group is formed when the -OH group of a carboxylic acid is replaced by −NH₂?

Acyl halide

Ester

Anhydride

Amide

The -OH group can be replaced by X, OR, and NH₂ to form halides, esters, and amides, respectively.

14 / 20

14) What is the product when ammonium acetate (CH₃COONH₄) is heated?

Acetic acid + Ammonia

Acetic anhydride + Water

Acetamide + Water

Ethyl acetate + Water

Ammonium salts formed by the reaction of carboxylic acids with ammonia produce acid amides upon heating (CH₃COONH₄ → CH₃CONH₂ + H₂O).

15 / 20

15) What is the product of the partial reduction of carboxylic acids with lithium aluminum hydride (LiAlH₄)?

Alkanes

Aldehydes

Ethers

Alcohols

Carboxylic acids on reaction with lithium aluminum hydride (LiAlH₄) are reduced to alcohols.

16 / 20

16) Which of the following is a key step in the mechanism of ester formation from carboxylic acids and alcohols?

Formation of a ketone intermediate

Protonation of the carboxylic acid

Deprotonation of the carboxylic acid

Elimination of an alkane

The first step in the mechanism of ester formation (esterification) is the protonation of the carboxylic acid.

17 / 20

17) The formation of an ester from a carboxylic acid and an alcohol in the presence of concentrated H₂SO₄ is known as:

Esterification

Hydrolysis

Amidation

Saponification

When carboxylic acids are heated with alcohols in the presence of concentrated H₂SO₄, esters are formed.

18 / 20

18) Which of the following is a common step in the mechanism of forming acyl chlorides from carboxylic acids using SOCl₂?

Addition of water

Reduction of the carbonyl group

Formation of a sulfinyl chloride intermediate

Protonation of the alkyl group

The mechanism for the reaction of CH₃COOH with SOCl₂ shows the formation of an intermediate where sulfur is bonded to the carboxyl oxygen and a chlorine atom.

19 / 20

19) What is the product formed when carboxylic acids react with NH₃ and are subsequently heated?

Ammonium salt only

Acid anhydride

Acid amide

Alkyl nitrile

Carboxylic acids react with ammonia to form ammonium salts which on heating produce acid amides.

20 / 20

20) What are carboxylic acids completely reduced to when reacted with HI and red phosphorus?

Alkanes

Aldehydes

Alkynes

Alkenes

Carboxylic acids on reduction with HI and red phosphorus give alkanes.

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