MCQ Questions for Class 12 Engineering Chemistry Aldehydes,Ketones And Carboxylic Acids Quiz 14

Which among the following carbonyl compound is most polar ?

Cyanogen

$(CN)_2$ on hydrolysis yields:

0%
malonic acid
0%
maleic acid
0%
formic acid
0%
oxalic acid

Explanation

Cyanogen

$(CN)_2$ on hydrolysis yields oxalic acid.

Which of the following cyanohydrins on hydrolysis give an optically active acid giving iodoform reaction?

0%
Acetone cyanohydrin
0%
Propionaldehyde cyanohydrin
0%
Acetaldehyde cyanohydrin
0%
Formaldehyde cyanohydrin

Explanation

Acetaldehyde cyanohydrin on hydrolysis give an optically active acid giving iodoform reaction.

This acid can be easily oxidized to contain

$CH_3CO$ group which is required for positive iodoform test.

Option C is correct.

In the reaction

$\text{X}$ is:

0%
$CH_3CH_2COOH$
0%
$CH_3COOH$
0%
$CH_3CH_2CHO$
0%
$CH_3CH_2OH$

Propanoic acid is obtained by the hydrolysis of:

0%
ethyl cyanide
0%
acetyl chloride
0%
acetamide
0%
all of the above

Carbonyl compounds gives nucleophilic addtion with :

0%
carbon nucleophile
0%
oxygen nucleophile
0%
Nitrogen nucleophile
0%
All of these

$(D)+Benzaldehyde\;\xrightarrow[(ii)\;H_2O^+]{(i)\;Pyridine,\;\Delta}\;Major\;Product\,(E)$
The major product

$(E)$ is

0%
Crotomic acid
0%
Cinnamic acid
0%
Benzoic acid
0%
Mandelic acid

Explanation

The organic compound (A) is 1,3-dichloropropane. On reduction with red

$P$ and

$Hl$ , it gives propane.

(A) on hydrolysis by an alkali followed by oxidation gives malonic acid (B). The

$-Cl$ groups of 1,3-dichloropropane are replaced with

$-OH$ groups to give propylene glycol. Primary alcoholic groups are then oxidized to carboxylic groups to give malonic acid. Malonic acid on heating gives acetic acid (C) by thermal decarboxylation of beta keto acid.

Both (B) and (C) give effervescence with

$NaHCO_3$ . This indicates presence of

$-COOH$ groups.

Malonic acid (B) on reacting with ethyl alcohol gives diethyl malonate (D) which is a well known synthetic agent. The next step is the condensation between benzaldehyde and diethyl malonate (D). A molecule of water is lost during condensation. In the next step, the ester groups are hydrolyzed. The final step is the thermal decarboxylation of beta keto acid to form cinnamic acid (E).

The

$pK_{a}$ values of four carboxylic acids are

$4.76, 4.19, 0.23$ and

$3.41$ respectively. The

$pK_{a}$ value of strongest carboxylic acid among them is:

0%
$4.19$
0%
$3.41$
0%
$0.23$
0%
$4.76$

Explanation

$K_a$ values is directly proportional to the strength of acid.
Whereas :

$pK_a$ value is inversely proportional to the strength of acid.
Means more the

$K_a$ value, more will be acidic strength , whereas :
Lesser the

$pK_a$ values , more the acidic strength.
Hence strongest acid is for the ,

$pK_a = 0.23$ and weakest acid is for the

$pK_a =4.76$ .

Acetic acid is prepared from ________.

0%
formaldehyde
0%
acetaldehyde
0%
vinyl acetate
0%
all of the above

Benzene carbaldehyde is reacted with concentrated

$NaOH$ solution to give the products

$A$ and

$B$ . The product

$A$ can be used as food preservative and the product

$B$ is an aromatic hydroxy compound where

$OH$ group is linked to

$sp^3$ hybridised carbon atom next to benzene ring. The products

$A$ and

$B$ respectively are :

0%
sodium benzoate and phenol
0%
sodium benzoate and phenyl methanol
0%
sodium benzoate and cresol
0%
sodium benzoate and picric acid

Explanation

Benzene carbaldehyde (benzaldehyde) is reacted with concentrated

$NaOH$ solution. It undergoes cannizzaro reaction where one molecule is oxidised to carboxylate ion and other molecule is reduced to alcohol. The products

$A$ and

$B$ respectively are sodium benzoate and phenyl methanol. The product

$A$ can be used as food preservative and the product

$B$ is an aromatic hydroxy compound where

$OH$ group is linked to

$sp^3$ hybridised carbon atom next to benzene ring. Hence, the option

$(B)$ is the correct answer.

Common name of 3-chloro, 2-butyric acid is:

0%
$\alpha$ - chloro, $\beta$ -methyl butyric acid
0%
$\beta$ - chloro, $\alpha$ -methyl butyric acid
0%
$\alpha$ , $\beta$ - chloro methyl butryic acid
0%
none of the above

Amongst the following compounds, the one(s) which readily react with ethanolic

$KCN$ ?

0%
Ethyl chloride
0%
Chloro benzene
0%
Benzaldehyde
0%
Salicylic acid

Explanation

The compounds which readily react with ethanolic KCN are ethyl chloride
and benzaldehyde.
Ethyl chloride reacts with ethanolic

$KCN$ to form propionitrile (major product) and ethylisocyanide (minor product).
Benzaldehyde reacts with ethanolic

$KCN$ and undergoes Benzoin condensation.

The boiling point of aldehyde and ketones depend upon:

0%
intermolecular dipole-dipole repulsion
0%
intermolecular dipole-dipole attraction.
0%
intermolecular induced dipole-dipole attraction.
0%
none of these.

Which of the following acids does not contain

$-COOH$ group?

0%
Carbamic acid
0%
Barbituric acid
0%
Lactic acid
0%
Succinic acid

Explanation

(a) Carbamic acid:

$HOOC - NH_{2}$

(b) Barbituric acid:

$C_{4}H_{4}N_{2}O_{3}$

$CH_{3}CH(OH)COOH$

(d) Succinic acid:

$HOOC - CH_{2} - CH_{2} - COOH$

Therefore, barbituric acid is actually not an acid.

Arrange the following compounds in the increasing order of their reactivity towards HCN.
I. Acetaldehyde
II. Acetone
III. Methyl-tert-butyl ketone
IV. Di-tert-butyl ketone

0%
III < II < IV < I
0%
II < I < IV < II
0%
IV < III < II < I
0%
II < IV < I < III

n-butyl benzene on oxidation will give:

0%
benzoic acid
0%
butanoic acid
0%
benzyl alcohol
0%
benzaldehyde

Explanation

In this reaction, the alkyl chain is oxidised to carboxylic acid in presence of oxidants like

$KMnO_4$ or chromic acid irrespective of the number of carbon atoms in the chain.

So the n-butyl benzene is converted into benzoic acid.

Hence option A is correct

IUPAC name of the compound is:

0%
3,4-Dihydroxybenzoic acid
0%
4,5-dihydroxybenzoic acid
0%
2,3-dihydroxybenzoic acid
0%
none of these

$R - CH_{2} - CH_{2} OH$ can be converted into

$RCH_{2}CH_{2}COOH$ by the following sequence of steps:

0%
$PBr_{3}, KCN, H_{2}/Pt$
0%
$PBr_{3}, KCN, H_{3}O^{+}$
0%
$HCN, PBr_{3}, H_{3}O^{+}$
0%
$KCN, H_{3}O^{+}$

Explanation

$\displaystyle R - CH_{2} - CH_{2} OH$ can be converted into

$\displaystyle RCH_{2}CH_{2}COOH$ by the following sequence of steps

$\displaystyle PBr_{3}, KCN, H_{3}O^{+}$

$\displaystyle R - CH_{2} - CH_{2} OH \xrightarrow {PBr_{3}} R - CH_{2} - CH_{2}-Br \xrightarrow {KCN} R - CH_{2} - CH_{2}-CN \xrightarrow {H_{3}O^{+}} RCH_{2}CH_{2}COOH$

When alcohol is treated with phosphorous tribromide, it gives alkyl bromide. Alkyl bromide reacts with

$KCN$ to form alkyl cyanide. In this process, one carbon atom is introduced. The hydrolysis of alkyl cyanide gives the carboxylic acid.

4-nitrotoluene is treated with bromine to get compound '

$P$ ' which is reduced with

$Sn$ and

$HCl$ to get compound '

$Q$ '. '

$Q$ ' is diazotized and the product is treated with phosphinic acid to get compound '

$R$ '. '

$R$ ' is oxidized with alkaline solution

$KMn{ O }_{ 4 }$ to get the final product. Identify the final product.

0%
2-bromo-4-hydroxybenzoic acid
0%
Benzoic acid
0%
4-bromobenzoic acid
0%
3-bromobenzoic acid
0%
2-bromobenzoic acid

Explanation

Given,

Step 1.

( $\because N{ O }_{ 2 }$ is $m$ -directing group while $C{ H }_{ 3 }$ group is $o-$ and $p-$ directing group. Thus, $Br$ group attach at $o-$ position with respect to $C{ H }_{ 3 }$ and $m$ -position with respect to $N{ O }_{ 2 }$ group)

Step 2. On reduction with ${ Sn }/{ HCl }, N{ O }_{ 2 }-$ group changes to $-N{ H }_{ 2 }$ group.

Step 3. On treatment with $NaN{ O }_{ 2 }+HCl$ ; $N{ H }_{ 2 }$ changes to diazo group (i.e. $Q$ shows diazotisation).

Step 4. On treatment with ${ H }_{ 3 }P{ O }_{ 2 }$ , only diazo group $\left( { N }_{ 2 }Cl \right)$ reacts and gets removed.

Step 5. On oxidation with ${ KMn{ O }_{ 4 } }/{ O{ H }^{ - } } - C{ H }_{ 3 }$ group changes to $-COOH$ group.

Oxidation of cyclohexene in presence of acidic potassium permanganate leads to.

0%
Glutaric acid
0%
Adipic acid
0%
Pimelic acid
0%
Succinic acid

Explanation

Oxidation of cyclohexene in presence of acidic potassium permanganate leads to Adipic acid.
Adipic acid is hexanedioic acid. The C=C double bond in cyclohexene is broken and the C atoms attached to double bond are oxidised to

$\displaystyle -COOH$ groups.

Trichloroacetaldehyde,

$CC{ l }_{ 3 }CHO$ reacts with chlorobenzene in presence of sulphuric acid and produces:

Explanation

From the above reaction trichloroacetaldehyde

$C{ Cl }_{ 3 }CHO$ reacts with chlorobenzene in presence of Sulphuric acid produces DDT

Hence option D is correct answer.

Which of the following is not a final product obtained by cross aldol condensation of ethanal and propanal?

0%
3-Methyl-but-2-enal
0%
2-Methyl-pent-2-enal
0%
But-2-enal
0%
Pent-2-enal

In the given reaction sequence :

Among the following sets of reactants, which one produces anisole?

0%
$CH_{3}CHO; RMgX$
0%
$C_{6}H_{5}OH; NaOH; CH_{3}I$
0%
$C_{6}H_{5}OH; neutral\ FeCl_{5}$
0%
$C_{6}H_{5} - CH_{3}; CH_{3}COCl; AlCl_{3}$

Explanation

The above reaction is the preparation of Anisole phenol

$+NaOH+C{ H }_{ 3 }I$ gives anisole.

${ C }_{ 6 }{ H }_{ 5 }OH, \ NaOH, \ C{ H }_{ 3 }I$ is the correct answer.

Identify the structure of

$M$ in the following sequence of reactions.

What is the formula of Acrolein?

0%
${ CH }_{ 2 }=CH-CHO$
0%
${ CH }_{ 2 }=CH-CN$
0%
${ CH }_{ 2 }=CN-COOH\quad$
0%
${ CH }_{ 2 }=CH-CO{ NH }_{ 2 }$

Explanation

Acrolein -

$C{ H }_{ 2 }=CH-CHO$

Which will undergo Friedel-Crafts alkylation reaction?

Which of the following reaction end with the same product?

0%
a, b, c
0%
a, c
0%
b, c
0%
a, b

Which is the correct method of synthesising acetamide from acetone?

0%
$CH_3COCH_3\xrightarrow{Pd/BaSO_4}CH_3CHO\xrightarrow{NH_3}CH_3CH_2NH_2\xrightarrow{H_2O}CH_3CONH_2$
0%
$CH_3COCH_3\xrightarrow[NaOH]{I_2}CH_3COONa\xrightarrow[NH_3]{H^+}CH_3COONH_4\xrightarrow{\Delta}CH_3CONH_2$
0%
$CH_3COCH_3\xrightarrow{CrO_3}CH_3COOH\xrightarrow{NH_3}CH_3CONH_2$
0%
$CH_3COCH_3\xrightarrow [NaOH]{I_2}CH_3COOH\xrightarrow {HCl}CH_3COCl\xrightarrow {NH_3}CH_3CONH_2$

Explanation

The best answer is B

$Pd/Baso_4$ cannot react with the ketone.

3 . in last step heating is required

4 . reaction of acid with acid is not possible.

The addition of

$HCN$ to carbonyl compounds is an example of:

0%
nucleophilic addition
0%
electrophilic addition
0%
free radical addition
0%
electromeric addition

Explanation

$HCN$ breaks and form

$CN^-$ ion and act as a nucleophile.

$CN^-$ attacks at carbonyl part, so it's a nucleophilic addition reaction.

Acetic acid is obtained when:

0%
methyl alcohol is oxidised with potassium permanganate
0%
calcium acetate is distilled in the presence of calcium formate
0%
acetaldehyde is oxidised with potassium dichromate and sulphuric acid
0%
glycerol is heated with sulphuric acid

Explanation

On oxidation of Acetaldehyde with oxidizing agents such as

${ K }_{ 2 }{ Cr }_{ 2 }{ O }_{ 7 }$ or

$KMn{ O }_{ 4 }$ gives acetic acid.

Acetic acid is obtained when acetaldehyde is oxidized with potassium dichromate and sulphuric acid.

Which of the following compound upon oxidation gives isophthalic acid?

0%
p-Xylene
0%
m-Xylene
0%
o-Xylene
0%
m-Cresol

$CH_3-CH=CH-CHO \xrightarrow[\Delta]{OH^{\circleddash}/H_2O}$
The major product which can be isolated from this reaction is:

0%
$CH_3COOH$
0%
$CH_3CHO$
0%
$CH_3CH_2OH$
0%

Which of the following would be the best synthesis of

$2, 2-dimethyl$ propanoic acid?

Which is the main functional group in Acrolein?

0%
Aldehyde
0%
Alkene
0%
Nitrile
0%
Ester

Explanation

Aldehyde

$( \displaystyle -\underset { \displaystyle \underset { \displaystyle O}{ || } }{ C}-H )$ is the main functional group in Acrolein.

In the above scheme of reactions,

$"X"$ is ?

Compounds formed during formation of product B and the final product B is:

Arrange the following compounds in increasing order of their reactivity in nucleophilic addition reactions.
Ethanal, Propanal, Propanone, Butanone

0%
Butanone < Propanone < Propanal < Ethanal
0%
Propanone < Butanone < Ethanal > Propanal
0%
Propanal < Ethanal < Propanone < Butanone
0%
Ethanal < Propanal < Propanone < Butanone

Above compound is hydrated maximum at which position?

0%
$1$
0%
$2$
0%
$3$
0%
equal

Explanation

Correct Option: $B$

Explanation

Hydration reaction refers to the addition of $H_2O$ molecule to a compound.
A hydration reaction is a nucleophilic addition reaction.
It is initiated by the addition of nucleophile $OH^-$ on a positive center.
Carbonyl groups are stable bonds but have very good nucleophile centers.
More is the positive polarity on the carbonyl carbon, easier is it for the nucleophile to attack.
The three carbonyl groups here are all $sp^2$ hybridized and thus in resonance.
Therefore, the two carbonyl groups ( $1$ and $3$ ) act as $-R$ as well as $-I$ groups, both of which are electron-accepting groups.
Thus, the most positive polarity is on $2$ carbonyl group.

Hence, the above compound is hydrated maximum at $2$ position

$Ph_2CH-\overset{O}{\overset{||}{C}}-H\overset{aqueous acid}{\rightarrow}\underset{81\%}{(A)}+\underset{2\%}{enol}+\underset{17\%}{aldehyde}$
Product (A) of given reaction will be.

0%
$Ph-\underset{Ph}{\underset{|}{C}}=CH-O$
0%
$Ph_2CH-\overset{OH}{\overset{|}{C}}H_2$
0%
$Ph_2CH-\overset{OH}{\overset{|}{C}}H-OH$
0%
$Ph_2CH-\overset{O}{\overset{||}{C}}-CH_3$

Explanation

In aqueous solutions at aldehydes hydrates are formed which are more stable.

$O$

$OH$

$O$

$ph_2CH-\overset {||}{C}-H\longrightarrow ph_2CH-\underset {|}{\overset {|}{C}}-H+ph_2-C=\overset {|}{C}-H+ph_2C-\overset {||}{C}-H$

$OH$

$17$ %

$OH$

$81$ %

$\Rightarrow ph_2CH-\overset {|}{CH}-OH$ ; Hydrates are formed if the

$\alpha-$ carbocation is stable.

Which of the following compounds are not oxidized by

$HIO_{4}$ ?

0%
$5, 6, 7$
0%
$4, 5, 6, 7$
0%
$6, 7$
0%
$3, 4, 5, 6, 7$

Explanation

$O$

$-OCH_3$ groups,

$-\overset {||}{C}-OH$ groups are not oxidized by

$HIO_4$ because

$-\underset {||}{C}-OH$ cannot be further oxidized and

$-OCH_3$ group is difficult to oxidize.

$O$

(Refer to Image)

1083220_992778_ans_45a5d65060de447d9e8503a37dce91d6.PNG

Product

$(D)$ in above reaction is:

Which of the following has lowest

$pK_a$ value?

Given the major organic product of the following reaction.

Explanation

Sodium acetylide is a nucleophilic which attacks on electrophilic carbons like carbonyl carbons.

Sodium acetylide

$\Rightarrow Na^+C^{\circleddash}\equiv C^{\circleddash}Na^+$

So, (Refer to Image)

1083167_993118_ans_8468f58592ff47b2bd58196b3f75813c.png

The compound

$(C)$ is:

Explanation

(Refer to Image)

The presence of

$SOCl_2, SN_1$ takes place in which retention of configuration occur. On addition of

$KCN$ again

$SN_2$ takes place. Then in presence of acid, hydrolysis of

$CN$ takes place and convert it into acid.

1097857_1068135_ans_f5579c41da5e4882a1ed26f8c7ae6408.png

The major product in the reaction of

$\alpha$ -bromo cyclohexanone with potassium ethoxide is?

The product of acid hydrolysis of [P] and [Q] can be distinguished by:

0%
Lucas reagent
0%
2,4-DNP
0%
Fehling's solution
0%
$NaHSO_{3}$

Arrange the following compounds in decreasing order of reactivity towards nucleophilic addition reaction:

${ C }_{ 6 }{ H }_{ 5 }COC{ H }_{ 3 }$
II)

$C{ H }_{ 3 }-COC{ H }_{ 3 }$
III)

$C{ H }_{ 3 }-CHO$

0%
I > II > III
0%
III > II > I
0%
II > I > III
0%
III > I > II

Choose the compound D from the following.

In the reaction CH

$_{3}$ OH

$\rightarrow$ HCOOH, the number of electrons that must be addad to the right is :

0%
4
0%
3
0%
2
0%
1

Explanation

Assign oxidation no.s for each atom in equation.

$C$ has changed its oxidation number from

$-2$ to

$+2$

$\left( +2 \right) -\left( -2 \right) =4$

${ CH }_{ 3 }OH\rightleftharpoons HCOOH+4{ e }^{ - }$

So,

$4$ electrons are to be added on right side.

1092152_1149255_ans_99801d1bfbd543c3a7e30f033f0fbf98.jpg

CBSE Questions for Class 12 Engineering Chemistry Aldehydes,Ketones And Carboxylic Acids Quiz 14 - MCQExams.com

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Practice Class 12 Engineering Chemistry Quiz Questions and Answers

CBSE Questions for Class 12 Engineering Chemistry Aldehydes,Ketones And Carboxylic Acids Quiz 14 - MCQExams.com

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Practice Class 12 Engineering Chemistry Quiz Questions and Answers

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