MCQ Questions for Class 12 Medical Chemistry Aldehydes, Ketones And Carboxylic Acids Quiz 7

$R - \overset{O}{\overset{||}{C}} - Cl \xrightarrow[conc. \,H_2SO_4]{NaN_3} \xrightarrow[]{CH_3 - Cl (1 \,eqvt.)} \underset{\left( \text{Major product} \right)}{P}$ Hence, Product

$(P)$ is:

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$R - NH_2$
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$R - NH - CH_3$
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$R - \overset{O}{\overset{||}{C}} - NH - CH_3$
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$R - NH - \overset{O}{\overset{||}{C}} - CH_3$

Explanation

Alkyl or aryl acyl chloride reacts with sodium azide to give acyl azides.

See the figure i.

The acyl azides undergo thermal decomposition to an isocyanate with loss of

$N_2$ gas. The isocyanate then undergoes nucleophilic attack to yield a primary amine.

See the figure ii and ii.

1122786_1125785_ans_68347a653b64489a8bcbf7a836c3345f.png

The Compound E is:

Explanation

Hydrolysis (complete) produces carboxylic acid from cyanide / nitriles.

So, correct answer is option

$A$ .

1380823_1131557_ans_a1d06ffa3ade42a2b35a3f9b71551758.png

$C_{4}H_{8}O_{2}$ represents:

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an acid only
0%
an ester only
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an ketone only
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an acid and an ester also

Explanation

$C_{4}H_{8}O_{2}$ represents an acid only.
1380503_1117995_ans_e805d6316e30422d8a9e8960aba5e651.jpg

Product is

When o-xylene is oxidised with alkaline

$KMnO_4$ , the product is:

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Terephthalic acid
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Phthalic acid
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Benzoic acid
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Salicylic acid

A tripeptide

$x$ on partial hydrolysis gave two dipeptides Cys-Gly and Glu-Cys.
Identify the tripeptide,

$\overset{+}{N}H_3 - \overset{CH_2CH_2COOH\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!}{\overset{\!\!\!\!\!\!|}{CH}} - \underset{Glu-Cys}{\underset{\!O}{\underset{||}{C}}} - NH - \overset{CH_2 SH\!\!\!\!\!}{\overset{\!\!\!\!\!\!|}{CH}} - \underset{O}{\underset{||}{C}} - \overset{-}{O}$

and

$\overset{+}{N}H_3 - \overset{CH_2SH\!\!\!\!\!\!\!\!}{\overset{\!\!\!\!\!\!|}{CH}} - \underset{Cys-Gly}{\underset{\!O}{\underset{||}{C}}} - NH - CH_2 - \underset{O}{\underset{||}{C}} - \overset{-}{O}$

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Glu-Cys-Gly
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Gly-Glu-Cys
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Cys-Gly-Glu
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Cys-Glu-Gly

Explanation

and

The tripeptide is Glu - Cys - Gly

Find the output

Explanation

$\bf{Hint:}$ It is a base-induced disproportionation reaction.

$\bf{Explanation:}$

In this reaction, two moles of aldehyde react to give a molecule of carboxylic acid and another molecule of primary alcohol. It belongs to the class of nucleophilic substitution reactions. It is also known as Cannizzaro Reaction.

$\bf{Mechanism:}$

$\bf{Final \ answer:}$ Option

$B$

Which of the following compounds gives an explosive on decarboxylation?

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$2,4,6-$ trinitrobenzoic acid
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$2,4-$ dinitrobenzoic acid
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$o-$ aminobenzoic acid
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$o-$ hydroxy benzoic acid

Identify

$X$

Explanation

Answer

$C.$ See the figure i.

Benzaldehyde undergoes cannizaro reaction with acetophenone in presence of a base. See the giver figure ii, ii and iv.

1127684_1135753_ans_0205d355f5494c9ca7b2443ee5d812fd.png

Which of the following substituted carboxylic acids has the highest

$K_a$ value?

Explanation

-IE groups increases

$K_{a}$ value of carboxylic acids. Here, -IE group is

$Cl^{-}$ as distance matters in inductive effect. Here,

$Cl^{-}$ is present in

$\alpha$ -carbon. Hence shows more

$K_{a}$ value.
1126840_1189626_ans_cff6af99db7a42cc8f50c52563b59289.png

Which of the following is/are more reactive towards nucleophilic addition reactions?

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$CH_3COCH_3$
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$HCHO$
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$CH_3CHO$
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$C_2H_5CHO$

When the reaction of

$Br_2$ with acetone is catalysed by hydroxide ion, which of the following are the likely products ?

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$CHBr_3$ and acetate ion
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Bromoacentic acid
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Tribromoacetic acid
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Acetyl bromide

Explanation

$O$

$\underset {Acetone}{CH_3-\overset {||}{C}-CH_3+Br_2 \xrightarrow []{{^\circleddash}OH}} \underset {Acetate Ion}{CH_3-\overset {||}{C}-O^{\circleddash}} +CHBr_3$

It is a type of Haloform reaction which takes place in presence of

$Br_2$ in basic medium.

What will be the prefix in the following compound ?

$HOOC - CH-2 - \overset{\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!HOOC - CH_2}{\overset{\!\!\!\!\!|}{CH}} - CH_2 - CH_2 - COOH$

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$methycarboxy$
0%
$carboxymethyl$
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$carboxyethyl$
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$ethylcarboxy$

Explanation

$2$ ,-carboxymethyl hexanedioic acid

The product "A" in the above reaction is:

Hunsdiecker reaction involves the conversion of

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$RCOOAg$ to $RCl$ using ${Cl}_{2}$
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$RCOOAg$ to ${(RCO)}_{2}O$ using $RCOCl$
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$RCOOAg$ to $RCOOR$ using ${I}_{2}$
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All the above

Compound X produces a carboxylic acid when heated under reflux with acidified potassium dichromate(VI). Compound X does not react with sodium metal.
What could be the identity of compound X?

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Propanal
0%
Propanone
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Propan- $1$ -ol
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Propan- $2$ -ol

Explanation

$\text{Ptopanal which is aldehyde gives carboxylic acid when heated under reflux with acidified potassium dichromate(VI)}$

$\text{It is a oxidation reaction.}$

$\text{Propanal does not react with Na metal.}$

Find the end product of reaction.

Explanation

Solution:- (D)

The end product of the reaction is

$1,2$ -dihydronaphthalen-

$2$ -one.

1301180_1631510_ans_ab1c7cfeecc944b9808d0081a37b2666.png

What is

$I$ and name of reaction?

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Aniline, Hoffmann bromamide reaction
0%
Sodium benzoate and Cannizaro reaction
0%
Phenyl isocyanide and cannizaro
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Phenyl isocyanide and carbylamine test

Which product is formed when

$3$ -methylpentane-

$1, 3, 4$ -triol is heated under reflux with an excess of acidified potassium dichromate(VI)?

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$HO_2CCH_2C(CH_3)(OH)COCH_3$
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$HO_2CCH_2COC(OH)(CH_3)_2$
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$OHCCH_2C(CH_3)(OH)COCH_3$
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$HO_2CCH_2CO(CH_3)COCH_3$

Explanation

Solution:- (A)

$HOOC-C{H}_{2}-\underset{\overset{|}{OH}}{\overset{\underset{|}{C{H}_{3}}}{C}}-\overset{\underset{||}{O}}{C}-C{H}_{3}$

${H}_{3}C-\overset{\underset{|}{OH}}{C{H}_{2}}-\underset{\overset{|}{OH}}{\overset{\underset{|}{C{H}_{3}}}{C{H}_{2}}}-C{H}_{2}-C{H}_{3}-OH \xrightarrow{{K}_{2}{Cr}_{2}{O}_{7} \left( \text{acidified} \right)} HOOC-C{H}_{2}-\underset{\overset{|}{OH}}{\overset{\underset{|}{C{H}_{3}}}{C}}-\overset{\underset{||}{O}}{C}-C{H}_{3}$

The acidified potassium dichromate

$\left( VI \right)$ will oxidise

$-OH$ group attached primary carbon to carboxylic group and secondary carbon to ketone.

Alcohols, aldehydes and nitriles can each be converted into carboxylic acids. Which descriptions of their conversions into carboxylic acids are correct?

	alcohols	aldehydes	nitriles
A	hydrolysis	hydrolysis	hydrolysis
B	hydrolysis	hydrolysis	oxidation
C	oxidation	oxidation	hydrolysis
D	oxidation	oxidation	oxidation

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A
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B
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C
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D

Explanation

$\text{1.Oxidation of alcohols converted into carboxylic acid.}$

$\text{2.Oxidation of aldehydes converted into carboxylic acid.}$

$\text{3.Nitriles can be converted into carboxylic acid by hydrolysis..}$

What are the suitable reagent for following conversion

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$Br_2/FeBr_3, KMnO_4, HNO_3 / H_2SO_4$
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$KMnO_4, Br_2/ FeBr_3, HNO_3$
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$HNO_3, Br_2 / FeBr_3, KMnO_4$
0%
$HNO_3, KMnO_4, Br_2 / FeBr_3$

The correct product of the following reaction is:

Explanation

Solution:- (A)

${C}_{6}{H}_{5}-{C}_{2}{H}_{5} \xrightarrow[{{H}_{3}O}^{+}]{\text{Alkaline } KMn{O}_{4}} \underset{\left( \text{Benzoic acid} \right)}{{C}_{6}{H}_{5}-COOH}$

Which of the following is isobutyric acid?

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${CH}_{3}{CH}_{2}{CH}_{2}COOH$
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${({CH}_{3})}_{2}CHCOOH$
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${CH}_{3}{CH}_{2}COOH$
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$(C_2H_5)CH(CH_3)COOH$

Explanation

Isobutyric acid, also known as 2-methyl propanoic acid is a carboxylic acid with structural formula

$(CH_3)_2CHCOOH.$

Hence option (B) is correct.

The general formula

${C}_{n}{H}_{2n}{O}_{2}$ could be for open chain:

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diols
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diketones
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carboxylic acids
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dialdehydes

Explanation

for example:

$C_2H_4O_2$ could be

$CH_3COOH$ {Acetic acid} or

$HO-CH=CH-OH$ {1,2-Ethenediol}

hence (A) and (C) are the correct options.

Which one of the following statements is wrong?

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Aldehydes and ketones are good reducing agents
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Aldehydes and ketones are polar compounds
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Aldehydes are more reactive than ketones
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Aldehydes and ketones are reduced to alcohols

${CH}_{3}CH_{2}I\xrightarrow [ ]{ KCN } \xrightarrow [ \Delta ]{ { H }_{ 2 }O }$
here the end product would be:

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2-cyanorpopanoic acid
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ethane-1,1-dicarboxylic acid
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2-methyl ethanoic acid
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propanoic acid

Explanation

Complete Reaction:

$\mathrm{CH_3-CH_2I \xrightarrow{KCN} CH_3CH_2-CN\xrightarrow[\Delta]{H_2O} \underset{Propanoic \ Acid}{CH_3CH_2COOH}}$

Hence, Option "D" is the correct answer.

Aldehydes are more reactive than ketones.

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True
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False

Which of the following has the highest

$p{K}_{a}$ value?

Explanation

The order of acidic strengths of given compounds is

$\mathrm{B>D>C>A}$

Stronger the acid is, lower is its

$\mathrm{pK_a}$ value.

So, the order of

$\mathrm{pK_a}$ values of given compounds is

$\mathrm{A>C>D>B}$

Hence, Option "A" is the correct answer.

Aldehydes are sweet smelling while ketones have pungent smell.

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True
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False

Carbonyl compounds undergo nucleophilic addition.

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True
0%
False

Which of the following as the lowest

$p{K}_{a}$ value?

Explanation

The acidic nature of compound depends on the stability of its conjugate base.

The order of acidic nature of given compounds is

$\mathrm{C>D>B>A}$ .

Greater the acidicity of an acid, lower is its

$\mathrm{pK_a}$ value.

So, the order of

$\mathrm{pK_a}$ value of given compounds is

$\mathrm{A>B>D>C}$

So, the lowest

$\mathrm{pK_a}$ value is of Benzoic acid.

Hence, Option "C" is the correct answer.

State, whether the following statements are True or False:
Benzamide on treatment with

$NaOH$ and

$Br_{2}$ forms benzoic acid.

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True
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False

Which of these does not contain

$-COOH$ group?

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Aspirin
0%
Benzoic acid
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Picric acid
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Salicylic acid

The compound is used as

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Antiseptic
0%
Antibiotic
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Analgesic
0%
Pesticide

Which of the following has lowest

$pK_{a}$ value?

Explanation

Closer is the electron-withdrawing group to the carboxylic group, greater is the acidic character of the compound.

Thus, option A has lowest

$pK_{a}$ value.

1549069_1726930_ans_2c84884f8bf2474d9fe247739a34debe.jpg

Soaps can be classified as:

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carbohydrates
0%
ethers
0%
salts of fatty acids
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none of these

The IUPAC name of the following compound is

$\begin{matrix} HOOC & - & { CH }_{ 2 } & - & CH & - & { CH }_{ 2 } & - & { CH }_{ 2 } & - & COOH \\ & & & & | & & & & & & \\ & & & & COOH & & & & & & \end{matrix}$

0%
$2-$ (Carboxy methyl)-pentane $-1,5-$ dioic acid
0%
$3-$ Carboxy hexane $-1,6-$ dioic acid
0%
Butane $-1,2,4-$ tricarboxylic acid
0%
$4-$ Carboxy hexane $-1,6-$ dioic acid
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$1,2$ dicarboxypentanoic acid

Explanation

The IUPAC name of the compound is Butane

$-1,2,4-$ tricarboxylic acid.

$\begin{matrix} HOOC & - & { \overset{1}CH }_{ 2 } & - & \overset{2}CH & - & { \overset{3}CH }_{ 2 } & - & { \overset{4}CH }_{ 2 } & - & COOH \\ & & & & | & & & & & & \\ & & & & COOH & & & & & & \end{matrix}$

The general formula for monocarboxylic acids is

0%
$C_nH_nCOOH$
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$C_nH_{2n+1}COOH$
0%
$C_nH_{2n-1}COOH$
0%
$C_nH_{2n}O_2$

Explanation

General formula of monocarboxylic acid is

$C_nH_{2n+1}COOH$ or

$C_nH_{2n}O_2$ .

Write the

$IUPAC$ name of

$CH_3CH_2COOH.$

0%
Ethyl formic acid
0%
Ethyl carboxylic acid
0%
Ethane methanoic acid
0%
Propanoic acid

Explanation

$\begin{matrix} \underset { 3 } { CH _ 3 } - \underset { 2 }{ { CH }_{ 2 } } - \underset { 1 }{ COOH } \\ & & \end{matrix}$

Propanoic acid

Which one is called ethanoic acid

0%
$HCOOH$
0%
$CH_3COOH$
0%
$CH_3CH_2COOH$
0%
$CH_3CH_2CH_2COOH$

The

$IUPAC$ name of succinic acid is

0%
$1,4-$ butanedioic acid
0%
Dimethyl $-2-$ acid
0%
$1,2-$ dimethyldioic acid
0%
None of these

Explanation

The IUPAC name of succinic acid is 1,4−butanedioic acid.

$\overset { 1 }{ C}OOH -\overset { 2 }{ { CH }_{ 2 }- } \overset { 3 }{ { CH }_{ 2 }- } \overset { 4 }{ C}OOH$

$1,4-$

$\text{butanedioic acid}$

Which of the following statement is correct about tropolone?

0%
0%
Tropolone has more stability and aromatic character than tropolone.
0%
Tropolone has higher dipole moment than tropone.
0%
Tropolone has lower boiling point than tropone.

Explanation

$\text{in stability and aromatic character}$
1622158_1757896_ans_5ab24eb685114dc0964242dbc1b37925.png

The typical reactions of aldehydes is :

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Electrophilic addition
0%
Nucleophilic substitution
0%
Nucleophilic addition
0%
Nucleophilic elimination

Explanation

Nucleophilic as addition of

$HCN , NaHSO_3$ etc.

When toluene is treated with

$KMnO_{4}$ , what is produced ?

0%
Benzene
0%
Chlorobenzene
0%
Benzaldehyde
0%
Benzoic acid

The above reaction is

0%
Electrophilic substitution
0%
Electrophilic addition
0%
Nucleophilic addition
0%
Nucleophilic substitution

Explanation

$\text{It is an example of nucleophilic addition reaction}$
1624129_1764709_ans_23a02fc37bc948bcb577171a4e715660.png

Order of reactivity is

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Acid Chloride > Acid Anhydride > Ester > Amide.
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Acid Chloride > Amide > Acid Anhydride > Ester
0%
Amide > Acid Anhydride > Ester > Acid Chloride
0%
Ester > Acid Chloride > Acid Anhydride > Amide.

By aerial oxidation, which one of the following gives phthalic acid

0%
Naphthalene
0%
Banzene
0%
Mesitylene
0%
Toluene

CBSE Questions for Class 12 Medical Chemistry Aldehydes, Ketones And Carboxylic Acids Quiz 7 - MCQExams.com

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Practice Class 12 Medical Chemistry Quiz Questions and Answers

CBSE Questions for Class 12 Medical Chemistry Aldehydes, Ketones And Carboxylic Acids Quiz 7 - MCQExams.com

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Practice Class 12 Medical Chemistry Quiz Questions and Answers

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