MCQ Questions for Class 12 Engineering Chemistry Aldehydes,Ketones And Carboxylic Acids Quiz 5

Identify the combination of compounds that undergo Aldol condensation followed by dehydration to produce but-2-enal:

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methanal and ethanal
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two moles of ethanal
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methanal and propanone
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ethanal and propanone

In the following reaction, the compound

$Z$ is:

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benzoic acid
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benzaldehyde
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acetophenone
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benzene

Lactic acid is formed, on hydrolysis of the cyanohydrin of

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Methanal
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Ethanal
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Propanal
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Propanone

Heptanol

$\underrightarrow { { CrO }_{ 3 }/{ H }_{ 2 }{ SO }_{ 4 } } \quad \quad ?$

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Heptanal
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Heptanoic acid
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Ethanal+ Proponal
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None of these

The IUPAC name of the compound shown here is

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5-Ethyl -1- hydroxyoctan -1, 4-dioic acid
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2-Carboxyethyl -3- hexyl ketone
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3-(3-Hexylcarbonyl) propanoic acid
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5-Ethyl-4-oxooctanoic acid

Explanation

Hint:- According to IUPAC Rules,

When 'ketone' is attached as a substituent (Secondary Prefix) it is named "oxo".

Step 1:

Nomenclature:

According to IUPAC rules,

The longest possible carbon chain including the functional group and multiple bonds should be considered as the parent carbon chain. The numbering should start from the carbon of the carboxylic acid as it has a higher priority than the ketone group in the priority order of the functional groups. It is an acid of

$8$ Carbons, so it is named as

$' octanoic\ acid'$ .

Step 2:

Alphabetical arrangement:

According to IUPAC rules,

An ethyl group is attached to the

$5th$ carbon of the parent chain, so it is named as

$'5-ethyl'$ . Ketone group is attached to the

$4th$ carbon so it is named as

$'4-oxo'$ . While arranging in alphabetical order,

$ethyl$ comes before

$oxo$ .

Final Step: Correct IUPAC name is

$5-Ethyl-4-oxooctanoic acid.$

So option D is the answer.

Arrange the given compounds in decreasing order of nucleophilic addition reaction:

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II> V> I> IV> III
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III> IV> I> V> II
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II> I> V> III> IV
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IV> III> V> I> II

The incorrect IUPAC name is

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$\underset{2 - methyl -3-butanone}{CH_3 \underset{O}{\underset{||}{C}} - \underset{CH_3}{\underset{|}{C}}H - CH_3}$
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$\underset{2, 3-dimethylpotane}{CH_3 \underset{CH_2}{\underset{||}{C}} - \underset{CH_2CH_3}{\underset{|}{C}}H - CH_3}$
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$\underset{2 - pentyne}{CH_3C \equiv C - CH_2 CH_3}$
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$\underset{2-bromo -3-chlore-butane}{CH_3\underset{Cl}{\underset{|}{C}}H - \underset{Br}{\underset{|}{C}}H - CH_3}$

Greatest amount of hydration is in:

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equal

Which of the following is correct order regarding the acidity of carboxylic acids?

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$\left( \mathrm { CH } _ { 3 } \right) _ { 3 } \mathrm { CCOOH } > \left( \mathrm { CH } _ { 3 } \right) _ { 2 } \mathrm { CHCOOH } > \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } \mathrm { COOH }$
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$\left( \mathrm { CH } _ { 3 } \right) _ { 3 } \mathrm { CCOOH } > \left( \mathrm { CH } _ { 3 } \right) _ { 2 } \mathrm { CHCOOH } < \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } \mathrm { COOH }$
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$\left( \mathrm { CH } _ { 3 } \right) _ { 3 } \mathrm { CCOOH } < \left( \mathrm { CH } _ { 3 } \right) _ { 2 } \mathrm { CHCOOH } > \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } \mathrm { COOH }$
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$\left( \mathrm { CH } _ { 3 } \right) _ { 3 } \mathrm { CCOOOH } < \left( \mathrm { CH } _ { 3 } \right) _ { 2 } \mathrm { CHCOOH } < \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } \mathrm { COOH }$

Which of the following is an example of nucleophilic addition to acetaldehyde?

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Acetal formation
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Cyanohydrin formation
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Bisulphite adduct
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Wolff-Kishner reaction

The major product of the given reaction is:

Consider the following reaction:

The compound

$D$ is an ortho-isomer and E is a

$p-isomer$ . The compounds

$D$ and

$E$ , respectively are :

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Phthalic acid and isophthalic acids
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Isophthalic and phthalic acids
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Terephthalic and phthalic acids
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Phthalic and terephthalic acids

Explanation

The compound D is a

$o-isomer$ and E is a

$p-isomer$ . The compounds D and E, respectively are Phthalic and terephthalic acids.

Give the products formed on reductive ozonolysis with LAH and oxidative ozonolysis with

$H_2O_2$ , from the compounds.

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Propan-1,3-diol and propan-1,3-dioic acid
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Propan-1,2-diol and propan-1,3-dioic acid
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Propan-1,3-diol and propan-1,2-dioic acid
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Propan-1,2-diol and propan-1,2-dioic acid

Explanation

In reductive ozonolysis with

$LAH$ or

$NaBH_4$ aldehyde and ketone are converted into alcohol and in oxidative ozonolysis with

$H_2O_2$ , the ketone remains unchanged and converts aldehyde to acid.

In the following sequence of reactions, products (A) to (H) are formed. Then the Compound (G) is :

Explanation

Compound (G) is represented by the option (A).

The compound (G) is cyclo-octa-1,3,5-triene. It is obtained from compound (F) (cyclo-octa-2-yn-1,4-diol). The reagents used are

(i) conc.

$\displaystyle H_2SO_4$

two molecules of water are eliminated to form two

$\displaystyle C=C$ double bonds.

(ii)

$\displaystyle H_2 +$ Lindlar's catalyst.

$\displaystyle C \equiv C$ triple bond is reduced to

$\displaystyle C=C$ double bond.

$P\xrightarrow {KMnO_{4}/KOH}Q\underset {\triangle}{\xrightarrow {Sodalime}} R \underset {anhy.\ AlCl_{3}}{\xrightarrow {CH_{3}Cl}} S$

$P$ and

$S$ are toluene,

$Q$ and

$R$ ______ and ______ respectively.

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Benzaldehyde, Benzoic acid
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Benzaldehyde, Sodium benzoate
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Benzoic acid, Benzene
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Benzene, Benzoic acid

Explanation

-Here P is Toluene.

When Toluene reacts with

$KMnO_4/KOH$ it undergoes oxidation reaction to form Benzoic acid (

$Q$ ) as a product.

This Benzoic acid when reacting with soda lime it forms back benzene (

$R$ ) as a product.

This benzene on reaction with

$CH_3Cl$ in the presence of Anhy.

$AlCl_3$ Undergoes Friedel-Craft's alkylation reaction to form Toluene as a product.

1335770_1646200_ans_e76ea6623827403cb240d3c1a3bdaf95.png

Propanoic acid occurs naturally as a result of the bacterial fermentation of milk and is partly responsible for the flavour of Swiss cheese.
Which starting materials can be used to produce propanoic acid?

${CH}_{3}{CH}_{2}{CH}_{2}OH$

${CH}_{3}{CH}_{2}CHO$

${CH}_{3}{CH}_{2}CN$

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1, 2 and 3 are correct
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1 and 2 only are correct
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2 and 3 only are correct
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1 only is correct

Which among the following compounds is used as selective weed killer?

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Picric acid
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$2, 4$ -dichlorophenoxy acetic acid
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$2, 4, 6$ -trichlorophenoxy acetic acid
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Salol

Explanation

2,4-dichlorophenoxy acetic acid (usually called as

$2,4-D$ ) is primarily used as a selective herbicide that selectively kills many terrestrial and aquatic broad leaf weeds, but not grasses.

It acts by mimicking the action of the plant growth hormone auxin, which results in uncontrolled growth and eventually death in susceptible plants.

Hence, option

$B$ is correct.

Cumene on treatment with

${KMnO_4}$ gives:-

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A
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B
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C
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D

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Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
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Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
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Assertion is correct but Reason is incorrect
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Both Assertion and Reason are incorrect

Which of the following cannot be used as reagent (B) ?

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$CH_3O\ominus$ at high temperature
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$C_2H_5O^\ominus$ at high temperature
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$CsOH + C_2H_5OH$

Explanation

Tert butoxide ion

$\displaystyle ((CH_3)_3-CO^-)$ at high temperature cannot be used as reagent (B). It is bulky base and will give Hoffmann product (less substituted alkene).
Saytzeff product (more substituted alkene) is obtained by reagent a, b, d (les-bulky base).

${pK_a}$ and

${K_a}$ of an acid are connected by the relation ---------

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${pk_a}$ = ${log k_a}$
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${pk_a}$ = ${- pH}$
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${pk_a}$ = ${- log k_a}$
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${pk_a}$ = ${- log k_b}$

Explanation

$pK_a$ is an index to express the acidity of weak acids.

$pK_a$ tells us how acidic (or not) a given hydrogen atom in a molecule is. The acidity

constant

$K_a= \dfrac {[H_3O^+][A^-]}{[AH]}$

This is also expressed in logarithmic form are follows:

$pK_a = -log_{10}(K_a)$

In the reaction
The product (A) is :

Explanation

In the reaction, product (A) is represented by the option (C).

Alpha beta unsaturated carbonyl compounds react with lithium dialkyl cuprate. This is an example of 1,4- addition or conjugate addition reaction. A

$C-C$ bond is formed in this reaction.

Cynohydrin of which of the following compound can give lactic acid

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$HCHO$
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$CH_{3}COCH_{3}$
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$CH_{3}CHO$
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$CH_{3}CH_{2}CHO$

Explanation

Cyanohydrin of acetaldehyde $CH_3CHO$ can give lactic acid.

In the reaction

$C_6H_6\, \xrightarrow[AlCl_3]{CH_3Cl}\, A\, \xrightarrow{KMnO_4}\, B$

$B$ is:

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benzoic acid
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benzoyl chloride
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benzaldehyde
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chlorobenzene

Explanation

${ C }_{ 6 }{ H }_{ 6 }\xrightarrow [ { CH }_{ 3 }Cl ]{ { AlCl }_{ 3 } } { C }_{ 6 }{ H }_{ 5 }{ CH }_{ 3 }\xrightarrow { { KMnO }_{ 4 } } { C }_{ 6 }{ H }_{ 5 }COOH$

The first reaction is Friedel craft alkylation reaction and then oxidation of toluene to give benzoic acid.

So. option A is correct.

The IUPAC name for the compound is:

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2-acetyl prop-1-ene
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pent-1-en-4-one
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Pent-4-en-2-one
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formyl propene

Polarisation of electron in acrolein

$\left(C{H}_{2}=CH-CH=O\right)$ or resonance hybrid of acrolein can be written as:

$HBr$ fails to give addition products with carbonyl compounds.
Is the above statement true?

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True
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False

Explanation

The addition of

$HBr$ to a carbonyl pi-bond is reversible and heavily favours the reactants thermodynamically, meaning the product is impossible to isolate, but the product is still an important intermediate for a host of other reactions. The reason nucleophile addiction is seen so much more than electrophilic addition is due to the instability of the carbocation compared with the oxygen anion. The above statement is true.

Aldehydes on oxidation gives_________

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Alcohol
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Acid
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Ketone
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Ether

3-Methyl-2-pentanone is :

Cyanohydrin of which of the following compound on hydrolysis gives optically active products?

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$HCHO$
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$CH_{3}CHO$
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$CH_{3}COCH_{3}$
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all of the above

Quinaine is obtained from-

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Bark
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Fruit
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Leaves
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Roots

Explanation

Quinaine

$\displaystyle \left ( C_{20}H_{24}O_{2}N_{2} \right )$ is obtained from the bark of Cinchona (Chinchona ledgeriana Linn.) tree by which quinic acid is made Its bark has 30% chemically related alkaloids

Acetylsalicylic acid is a pain killer and is commonly known as

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paracetamol
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aspirin
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ibuprofen
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penicillin

Functional group of carboxylic acid is:

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$RO-$
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$-C-OH$
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$-OH$
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$-COOH$

Explanation

The functional group of carboxylic acid is

$R-COOH$

where R is the Alkyl group and in nomenclature, they are named as -oic acids.

like carbonic acid, formic acid, Acetic acid etc..

Ethanol on reaction of acidified potassium dichromate form:

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ethane
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ethene
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ethanal
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ethanoic acid

Explanation

$C_2H_5OH + K_2Cr_2O_7/ {H}^{+} \rightarrow CH_3CHO \rightarrow CH_3COOH$

Ethanol is first oxidised to ethanal and then to ethanoic acid.
Potassium dichromate is a very strong oxidising agent, ethanol on oxidation, the dichromate ion (IV) solution which is orange in colour is reduced to a green colour Cr(III) ion solution. This reaction is used in detecting the presence of alcohol in breath in suspected drunken drivers.

Hence, the correct option is D.

Chlorinaton of toluene in the presence of light and heat followed by treatment with aqueous NaOH gives

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o-cresol
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p-cresol
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salt
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benzoic acid

The major product in the following at

$25^oC$ is:

$CH_3COOH\xrightarrow {CH_3CH_2NH_2}$

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$CH_3CONHCH_2CH_3$
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$CH_3CH=NCH_2CH_3$
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$NH_3^+CH_2^-CH_3.CH_2COO^-$
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$CH_2CON=CHCH_3$

The order or reactivity of phenyl magnesium bromide with the following compounds is:

(I)

$CH_3-\overset{\displaystyle O}{\overset{\displaystyle ||}{C}}-CH_3$

(II)

$H-\overset{\displaystyle O}{\overset{\displaystyle ||}{C}}-CH_3$

(III)

$Ph-\overset{\displaystyle O}{\overset{\displaystyle ||}{C}}-Ph$

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(II)> (III) > (I)
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(I) > (III)> (II)
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(II) > (I) > (III)
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all react with the same rate

Explanation

This is nucleophilic addition reaction to carbonyl group as the Grignard reagent acts as nucleophile.

The carbon atom of

$C=O$ group should be more electron defecient for faster attack of nucleophile.

Aldehydes have less electron-density than ketones, hence aldehydes are more reactive than ketones.

The steric hinderance also affect the reactivity, so the III is least reactive due to bulky phenyl rings which slows down the nucleophilic attack.

Option C is correct.

Out of the following the one that undergoes reaction with 50% NaOH solution to give corresponding alcohol and acid is:

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phenol
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benzaldehyde
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butanol
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benzoic acid

Explanation

The reaction of benzaldehyde to form alcohol and acid can be written as:

$C_{6}H_{5}CHO \xrightarrow[H_{3}O^{-}]{NaOH} C_{6}H_{5}COOH + C_{6}H_{5}CH_{2}OH$

The reaction is also called as Cannizzaro's reaction. This reaction can be given by only those aldehyde which does not contain alpha carbon.

Among the following acid which has the lowest

$pK_a$ ?

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$CH_3CH_2COOH$
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$(CH_3)_2CH-COOH$
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$HCOOH$
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$CH_3COOH$

Explanation

Acidity

$\propto \cfrac 1{pK_a} \propto \cfrac{1}{+I-effect}$

Stronger the acid lower is the pK value. From the given acid HCOOH is the strongest acid as it do not have any +I group.
Option C is correct.

$A$ reacts with

$NaOI$ followed by the reaction with

$H^+$ to give

$3,\,4-$ dihydroxybenzoic acid. What is

$A$ ?

In deodorant soaps, the additive added is:

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glycerol
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stearic acid
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potassium bicarbonate
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3,4,5-tribromo salicylaldehyde

${ CH }_{ 3 }CHO+HCHO\xrightarrow [ Dil.\ NaOH ]{ Heat } A\xrightarrow [ HCN ]{ { { H }_{ 3 }O }^{ + } } B$

The structure of compound

$B$ is :

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$CH_3-\underset{OH}{\underset{|}{C}H}-COOH$
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$CH_2=CH-\underset{CN}{\underset{|}{C}H}-OH$
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$CH_3CH_2-\underset{OH}{\underset{|}{C}H}-COOH$
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$CH_2=CH-\underset{OH}{\underset{|}{C}H}-COOH$

Explanation

It undergoes aldol condensation to give

$CH_2(OH)CH_2(CHO)$ which dehydrates to give

$CH_2CHCHO$

When this is treated with

$HCN/H_3O^+$ , it gives the carboxylic acid.

$CH_3CHO+HCHO\xrightarrow { Dil.NaOH } CH_2(OH)CH_2CHO$

$CH_{ 2 }(OH)CH_{ 2 }CHO\xrightarrow { \Delta } CH_2=CHCHO$

$CH_{ 2 }=CHCHO\xrightarrow { HCN } CH_2=CHCH(OH)(CN)$

$CH_{ 2 }=CHCH(OH)(CN)\xrightarrow { { H_{ 3 }O }^{ + } } CH_{ 2 }=CH-CH(COOH)(OH)$

Ethyl ethanoate on reacting with excess of

${CH}_{3}MgBr$ will give

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acetone
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2-methyl-2-propanol
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isobutanol
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n-butyl alcohol

Explanation

Ethyl ehtanoate on reacting with excess of

${CH}_{3}MgBr$ gives 2-methyl-2-propanol.
1316704_460711_ans_d67ffbb992eb4adea61587248d92387b.png

Identify the compounds which give yellow precipitate with

${I}_{2}+NaOH$
(a) Ethyl alcohol (b) Acetone
(c) Propyl alcohol (d) 2-propanol
(e) 3- butanone (f) Butanal

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c, e and f
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a, d and f
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e, f and a
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a, b and d

Which of the following acids is hydroxy acid?

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Maleic acid
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Succinic acid
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Lactic acid
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Adipic acid

Explanation

Lactic acid is a hydroxy acid because it contains both groups ie,

$-OH$ and

$-COOH$ groups
1316743_461872_ans_82e783aa5582458eba0fa83ae74eb4e1.png

In the sequence of reaction:

$C_2H_2\xrightarrow[HgSO_4]{H_2SO_4}A\overset{[O]}{\longrightarrow}B$

The compound B is:

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ethanoic acid
0%
propanone
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ethanol
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methanal

You can make an organic acid from ethanol and that is:

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$\displaystyle { C }_{ 3 }{ H }_{ 7 }OH$
0%
found in bees and ants
0%
acetic acid
0%
formic acid
0%
butanoic acid

The

$\displaystyle p{ K }_{ a }$ values of four carboxylic acids are given below. Identify the weakest carboxylic acid.

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4.89
0%
1.28
0%
4.76
0%
2.56

A tripeptide is written as glycine-alanine-glycine. The correct structure of the tripeptide is:

Structure of ethanoic acid is:

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$\displaystyle { CH }_{ 3 }-{ CH }_{ 2 }-{ CH }_{ 3 }$
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$\displaystyle CH_3-\underset {\displaystyle \underset {\displaystyle O}{ ||}}{C}-OH$
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$\displaystyle { CH }_{ 3 }-O-{ C }_{ 3 }{ H }_{ 7 }$
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$\displaystyle CH_3-\underset {\displaystyle \underset {\displaystyle O}{ ||}}{C}-CH_3$
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$\displaystyle CH_3 - CH_2- NH_2$

Explanation

Structure of ethanoic acid is

$\displaystyle CH_3-\underset {\displaystyle \underset {\displaystyle O}{ ||}}{C}-OH$ . It is also called acetic acid. It can be considered as compound formed by substituting the hydrogen atom of methane with carboxylic group

$-COOH$ .

CBSE Questions for Class 12 Engineering Chemistry Aldehydes,Ketones And Carboxylic Acids Quiz 5 - 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 5 - MCQExams.com

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Practice Class 12 Engineering Chemistry Quiz Questions and Answers

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