MCQ Questions for Class 12 Medical Chemistry Alcohols, Phenols And Ethers Quiz 4

$CH_3-\underset{CH_3}{\underset{|}{C}H}-\underset{OH}{\underset{|}{C}H}-\underset{CH_3}{\underset{|}{\overset{CH_3\!\!\!\!\!}{\overset{|}{C}}}-}CH_3$

The IUPAC name of the above given compound is:

0%
2,2,4-Trimethylpentan-3-ol
0%
2,4,4-trimethylpentan-3-ol
0%
2-methyl-1-(2-methylpronyl)-propanol
0%
none of the above

Explanation

$\overset{5}CH_3-\underset{CH_3}{\underset{|}{C}\overset{4}H}-\underset{OH}{\underset{|}{\overset{3}C}H}-\underset{CH_3}{\underset{|}{\overset{CH_3\!\!\!\!\!}{\overset{2|}{C}}}-}\overset{1}CH_3$

The compound has 2 methyl groups at carbon number 2 and one methyl group at carbon number 4.

Functional group

$-OH$ (ol) is attached at carbon number 3

So its name is 2, 2, 4-Trimethylpentan-3-ol.

Option A is correct.

Which of the following is the most basic in character?

0%
$\displaystyle H_{2}O$
0%
$\displaystyle CH_{3}CH_{2}OH$
0%
$\displaystyle CH_{3}OCH_{3}$
0%
$\displaystyle CH_{3}OH$

$CH_3 - \underset{OH}{\underset{|}{\overset{CH_3}{\overset{|}{C}}}} - CH_2 - CH_3$

The correct IUPAC name of the above compound is:

0%
tert- amyl alcohol
0%
2-methylbutan-2-ol
0%
2-methylpentan-2-ol
0%
1,1 dimethyl propan-1-ol

IUPAC name of the given compound is:

0%
5-ethylheptane-2.4-diol
0%
3-ethylheptane-4,6-diol
0%
4-ethyl-1-methylhexane-1,3-diol
0%
none of these

Explanation

The compound have ethyl group at carbon no

$5$ , two hydroxyl groups at carbon no

$2$ and

$4$ . So its name is

$5-$ ethylheptane

$-2.4-$ diol.

Which of the following is wood alcohol?

0%
$\displaystyle CH_{3}OH$
0%
$\displaystyle C_{2}H_{5}OH$
0%
1-Butanol
0%
2-Methyl -1-propanol

Explanation

Methanol, also known as methyl alcohol, wood alcohol, wood naphtha, methyl hydrate, or wood spirits, is a chemical with the formula CH₃OH.

Methanol acquired the name wood alcohol because it was once produced chiefly by the destructive distillation of wood

Hence, the correct option is

$\text{A}$

Which of the following is most acidic?

0%
Benzyl alcohol
0%
2- Butanol
0%
tert-Butyl alcohol
0%
Hydroxybenzene

Explanation

The acidic strength of alcohols can be explained on the basis of the stability of conjugate bases.

The conjugate base of hydroxybenzene

$(C_6H_5OH)$ is phenolate

$(C_6H_5O^-)$ ion which is very stable due to charge delocalization or resonance of charge in the ring. Therefore it is most acidic.

The conjugate base of benzyl alcohol does not show resonating structures thus it is not stable.

$2-$ Butanol and tert-Butyl alcohol posses

$+I$ inductive effect of alkyl groups which make them less acidic.

Hence, the correct option is

$\text{D}$

Which of the following is produced during the following reaction?

$\displaystyle CO\left ( g \right )+H_{2}\left ( g \right )\xrightarrow[ZnO,Cr_{2}O_{3}]{575 K}$

0%
Ethanol
0%
Ethanal
0%
Methanol
0%
Methanal

Explanation

Methanol is produced during the following reaction

$\displaystyle CO\left ( g \right )+H_{2}\left ( g \right )\xrightarrow[ZnO,Cr_{2}O_{3}]{575 K} CH_3OH$ .

A mixture of CO and hydrogen (1:2 molar ratio) is called synthetic gas.

It is heated to a temperature of 573 K in presence of

$ZnO/ Cr_2O_3$ catalyst to form methanol.

It is industrial method of preparation of methanol.

Option C is correct.

The

$K_a$ values of alcohols, water and phenol are of order

$10^{17}, 10^{14}$ and

$10^{10}$ respectively. Which of the following reactions is possible?

$(I)\,\,C_6H_5O^\circleddash + H_2O \rightarrow C_6H_5OH + OH^\circleddash$

$(II)\,\, C_2H_5O^\circleddash + H_2O \rightarrow C_2H_5OH + OH^\circleddash$

0%
Both I and II
0%
Only II
0%
Only I
0%
Neither of two

When 3-methylbutan-2-ol is treated with HBr, the following reaction takes place. What are the correct steps for formation of the above product?

0%
Formation of carbocation $\rightarrow$ Nucleophilic attack by $Br^\ominus$
0%
Formation of carbocation $\rightarrow$ 1,2 hydride shift $\rightarrow$ Nucleophilic attack by $Br^\ominus$
0%
Formation of carbocation $\rightarrow$ 1,2 methyl shift $\rightarrow$ Nucleophilic attack by $Br^\ominus$
0%
None of these

Consider the reaction between

$\displaystyle C_{2}H_{5}O^{\circleddash }$ and dimethyl sulphate. The leaving group in this reaction is

0%
$\displaystyle MeOSO_{2}O^{\circleddash }$
0%
$\displaystyle MeO^{\circleddash }$
0%
$\displaystyle Me^{\circleddash }$
0%
$\displaystyle MeOSO_{2}^{\circleddash }$

Solubility of alcohols in water is _______ to that of hydrocarbons of comparable molecular masses.

0%
greater than
0%
similar
0%
lesser than
0%
none of these

Explanation

Since alcohols can participate in

$H-$ bonding while hydrocarbons cannot, alcohols are able to interact with water molecules more easily than hydrocarbons of comparable molecular masses. Hence alcohols possess greater solubility in water than hydrocarbons of comparable molecular masses.

The IUPAC name of the following compound is:

0%
1-cyclopentene-4-ol
0%
3-cyclopenten-1-ol
0%
3-hydroxy cyclopentene
0%
4-hydroxy cyclopentene

Lower alcohols are highly soluble in water due to _____.

0%
van der Waal's attraction
0%
dipole dipole interaction
0%
steric hindrance
0%
H-bonding

Phenol on reaction with

$\displaystyle { NH }_{ 3 }$ gives :-

0%
Aniline
0%
Nitrobenzene
0%
Benzaldehyde
0%
Anilinium chloride

Explanation

Phenol on reaction with ammonia gives aniline. In this reaction, -OH group is replaced with $-NH_2$ group.

The product obtained in the above reaction is:

0%
0%
0%
$\displaystyle RCH=CHCOOH$
0%
none of these

Explanation

When

$\beta$ hydroxy acid is heated, it undergoes dehydration to form

$\alpha, \beta$ unsaturated acid.

$\displaystyle RCHOHCH_2COOH \xrightarrow [dehydration] {\Delta} RCH=CHCOOH$

Carbinol is a trivial name of :-

0%
$\displaystyle { C }_{ 2 }{ H }_{ 5 }OH$
0%
$\displaystyle { CH }_{ 3 }OH$
0%
$\displaystyle HCOOH$
0%
$\displaystyle { CH }_{ 3 }COOH$

Explanation

Carbinol is a trivial name of methanol $CH_3OH$ .

Heating together of sodium ethoxide and ethyl iodide will give:

0%
ether
0%
ethyl alcohol
0%
acetaldehyde
0%
acetic acid

The acidity of phenol is due to the _____ of its anion.

0%
keto-enol tautomerism
0%
electron withdrawing nature
0%
hyperconjugation
0%
resonance stabilisation

With ethoxyethane which compound is miscible to almost the same extent?

0%
Formaldehyde
0%
Bhutanone
0%
Butan-1-ol
0%
Propan-1-ol

Explanation

The correct option is

$C$ . Ethoxyethane is an ether group which is miscible to the alcohol that is Butan

$-1-$ ol. This is because they have the same molecular mass.

Lower alcohols are more soluble in water than higher alcohols.

0%
True
0%
False

Explanation

Lower alcohols are more soluble in water than higher alcohols. With the increase in the molar mass, solubility decreases. In alcohols,

$-OH$ group is polar and forms hydrogen bonds with water. This makes alcohol water soluble. The alkyl chain (hydrocarbon chain) is non-polar and decreases the solubility of alcohol in water.

The correct reactivity order of alcohols towards

$H-X$ will be:

0%
$\;II>I>III>IV$
0%
$\;IV>III>II>I$
0%
$\;II>IV>I>III$
0%
$\;II>IV>III>I$

Explanation

The correct reactivity order of alcohols towards H−X will be

$\displaystyle II>IV>III>I$

Alcohol II has maximum reactivity as the carbocation formed will be stabilized by resonance with adjacent C=C double Bond.

Alcohol I has minimum reactivity as the carbocation formed will have positive charge on

$\displaystyle sp^2$ carbon atom.

Alcohol IV is more reactive than alcohol III because alcohol IV gives secondary carbocation whereas alcohol III gives primary carbocation.

Secondary carbocation is more stable than primary carbocation.

Electrophilic substitution reaction in phenol takes place at:

0%
para position
0%
meta position
0%
ortho position
0%
ortho and para position

Explanation

Electrophilic substitution reaction in phenol takes place at ortho and para position.

$-OH$ is an ortho para directing group.

The electron density at ortho and para positions will be higher than the electron density at meta position.

Which of the following is a primary alcohol ?

0%
Butan - 2 - ol
0%
2 - Methylpropan -1- ol
0%
2 - Methylpropan - 2- ol
0%
None of the above

Explanation

$CH_{3}-CH(CH_{3})-CH_{2}-OH$ is a primary alcohol as hydroxal group; -OH is attached to the primary carbon.

The major product obtained on acid - catalysed hydration of 2-phenylpropene is:

0%
2-phenylpropan-2-ol
0%
2-phenylpropan-1-01
0%
3-phenylpropan-2-ol
0%
1-phenylpropan-1-ol

Explanation

The major product obtained on acid - catalysed hydration of 2-phenylpropene is 2-Phenylpropan-2-ol. A molecule of water is added to

$\displaystyle C=C$ double bond.

$\displaystyle -OH$ group is added to more substituted C atom.

Among ethanol, dimethyl ether, methanol and propanal, the isomers are

0%
ethanol, dimethyl ether, methanol and propanal
0%
ethanol and methanol
0%
ethanol, dimethyl ether, and methanol
0%
ethanol and dimethyl ether

Explanation

Ethanol

$(C_2H_5OH)$ and dimethyl ether

$(CH_3-O-CH_3)$ have same molecular formula but different functional groups, so they are isomers.

The major product of the above reaction is:

Refer the given reactions and answer the following questions:

Identify X, Y and Z respectively:

0%
$\displaystyle CH_{3}COOH,CH_{2}= CH_{2},CH_{3}COOCH_{3}$
0%
$\displaystyle CH_{2}= CH_{2},CH_{3}COOH,CH_{3}COOCH_{2}CH_{3}$
0%
$\displaystyle HCHO,CH_{3}CH_{3},CH_{3}CH_{2}COOH$
0%
$\displaystyle CH_{3}CH_{3},HCHO,CH_{3}COOH$

Explanation

Reactions:

$CH_3CH_2OH \xrightarrow {conc. H_2SO_4} CH_2 = CH_2$

$CH_3CH_2OH \xrightarrow {oxidation} CH_3COOH$

Identify the stereoisomeric pair from the following choices

0%
$CH_3 CH_2 CH_2 OH$ and $CH_3 CH_2 OCH_3$
0%
$CH_3 CH_2 CH_2 Cl$ and $CH_3 CHClCH_3$
0%
0%

Among the four compounds (i) acetone, (ii) propanol, (iiii) methyl acetate and (iv) propionic acid, the two that are isomeric are

0%
methyl acetate and acetone
0%
methyl acetate and propanol
0%
propionic acid and methyl acetate
0%
propionic acid and acetone

Explanation

Propionic acid and methyl acetate both have same molecular formula

$(C_3H_6O_2)$ but different functional groups, so they are isomers.

Which of the following is correct for stability of phenoxide ion?

0%
Resonating structure of benzene ring
0%
Localization of $\pi$ -electrons in phenoxide ion
0%
Delocalization of $\pi$ -electrons in phenoxide ion.
0%
All of the above

Phenol is more acidic than that of ethanol because:

0%
phenoxide ion is bulkier then ethoxide
0%
phenoxide ion is stronger base than ethoxide
0%
phenoxide ion is stabilised through delocalisation
0%
phenoxide ion is less stable than ethoxide

A vicinal diol has two alcoholic groups present :

0%
on the same carbon
0%
on adjacent carbon atoms
0%
anywhere along the carbon chain
0%
none of the above

The product formed by decolourization of

$KMn{O}_{4}$ by ethylene is _________ which is used as ______.

0%
ethane, oxidant
0%
ethyl alcohol, coolant
0%
ethylene glycol, antifreeze
0%
ethanol, reductant

Explanation

When ethylene react with

$KMnO_4$ , than pink colour of

$KMnO_4$ gets disappear and ethylene gets converted with ethylene glycol.
1175537_399041_ans_bc430365b5784ec09f0afad669a43e29.PNG

Which among the following reactions does not give methyl alcohol?

0%
The reaction of ethylene with ${H}_{2}{SO}_{4}$ at ${80}^{o}C$
0%
The reaction of water gas with hydrogen at high temperature
0%
Alkaline hydrolysis of methyl bromide
0%
Both $A$ and $B$

Explanation

The reaction of ethylene with

${H}_{2}{SO}_{4}$ at

${80}^{o}C$ gives ethyl hydrogensulphate.

$CH_2=CH_2+H_2SO_4 \rightarrow CH_3CH_2OSO_2OH$
Water gas (carbon monoxide and hydrogen) at high temperature gives methanol.

$CO + 2H_2 \rightarrow CH_3OH$ .
Alkaline hydrolysis of methyl bromide gives methanol

$CH_3Br + H_2O \rightarrow CH_3OH + HBr$

The IUPAC name of

$CH_3\, -\, C(CH_3) (OH) CH_2\, -\, CH(CH_3)\, CH_3$ is :

0%
2, 4 - Dimethylpentan - 2 - ol
0%
2, 4 - Dimethylpentan - 4 - ol
0%
2, 2 - Dimethylbutane
0%
Isopentanol

What are the types of reactions occurring in the formation of X, Y and Z respectively?

0%
Oxidation, Reduction, Substitution
0%
Substitution, Esterification, Dehydration
0%
Reduction, Substitution, Oxidation
0%
Dehydration, Oxidation, Esterification

Explanation

Reactions:

$CH_3CH_2OH \xrightarrow {conc. H_2SO_4} CH_2 = CH_2$ dehydration

$CH_3CH_2OH \xrightarrow {oxidation} CH_3COOH$ oxidation
esterification

Alcohols containing only up to ________________ carbon atoms are completely miscible with water.

0%
10
0%
3
0%
8
0%
14

Explanation

Alcohol-containing up to

$3-$ carbon atoms are completely miscible with water in all proportions. This is due to the hydrogen bonding with water molecule.

Methanol is now prepared from:

0%
water gas
0%
sugar through fermentation
0%
wood
0%
both $A$ and $B$

The molecular formula of ethanol is :

0%
$(CH_3)_2 CHOH$
0%
$C_2 H_5 OH$
0%
$CH_3 OH$
0%
$CH_3 CH_2 CH_2 OH$

Explanation

$(CH_3)_2CHOH$ is 2-propanol or isopropyl alcohol,

$CH_3OH$ is methanol,

$CH_3CH_2CH_2OH$ is 1- propanol or isopropyl alcohol.

The compound in option B is ethanol. It is hydroxyl derivative of ethane.

What is the common name of methyl alcohol?

0%
Wine
0%
Wood spirit
0%
Dilute acid
0%
None of the above

Glycol is a:

0%
primary alcohol
0%
dihydric alcohol
0%
secondary alcohol
0%
trihydric alcohol

The suffix used in the nomenclature of alcohol is:

0%
'al'
0%
'ol'
0%
'yl'
0%
'one'

Propene on hydration gives

0%
propan-1-ol
0%
propan-2-ol
0%
propanal
0%
methoxy ethane

The compound which reacts fastest with Lucas reagent at room temperature, is

0%
butan-1-ol
0%
butan-2-ol
0%
2-methyl propan-1-ol
0%
2-methyl propan-2-ol

What amount of bromine will be required to convert

$2\ g$ of phenol into

$2, 4, 6-tribromophenol$ ?

0%
$4.00$
0%
$6.00$
0%
$10.22$
0%
$20.44$

Explanation

Write equation for chemical change, find molecular masses of reactants and products and solve it.
Molecular weight of phenol

$= 12\times 6 + 1 \times 6 + 16 = 94$
Molecular wt. of

$Br_{2} = 3\times 160 = 480$

$\because 94$ of phenol requires

$= 480\ g$ of

$Br_{2}$

$\therefore 2\ g$ of phenol requires

$= \dfrac {480}{94} \times 2 = 10.22\ g$

The correct answer is 10.22 g

1056479_461928_ans_f36e0ab2bf844e8e9faab61125e74f3b.png

Sodium phenoxide

$\xrightarrow [ pressure ]{ { CO }_{ 2 } } A \xrightarrow [ ]{ { { H }_{ 3 }O }^{ + } }$ o-hydroxy benzoic acid
This product can also be obtained by the reaction of which of the following?

0%
Phenol + chloroform +alkali
0%
Phenol + pyrene + alkali
0%
Phenol + acetyl chloride + $Al{Cl}_{3}$
0%
Phenol + methyl chloride + $Al{Cl}_{3}$

Which statement is incorrect?

0%
Phenol is a weak acid
0%
Phenol is an aromatic compound
0%
Phenol liberates $C{ O }_{ 2 }$ from ${ Na }_{ 2 }C{ O }_{ 3 }$ solution
0%
Phenol is soluble in $NaOH$

Explanation

Only the acids stronger than carbonic acid are able to liberate

$C{O}_{2}$ from

${Na}_{2}C{O}_{3}$ solution.
Since, phenol is a weak acid, it does not liberate

$C{O}_{2}$ from

${Na}_{2}C{O}_{3}$ solution.

The miscibility of ether with _______ resembles those of alcohol of the same molecular mass.

0%
methanol
0%
water
0%
DCM
0%
benzene

Explanation

The miscibility of ether with water resembles those of alcohol of the same moleculer mass. It is generally due to the hydrogen bonding with water in alcohol. So the correct option is

$B$ .

Identify the major product X obtained in the following reaction.

$2, 3-\text{dimethyl butan}-2-ol\xrightarrow []{Conc.H_{ 2 }SO_{ 4 }} X$

Explanation

Dehydration of alcohol occurs when the reaction proceeds in the presence of sulphuric acid.

$({ CH_{ 3 }) }_{ 2 }HC-C(OH)({ CH_{ 3 }) }_{ 2 }\longrightarrow { (CH_{ 3 }) }_{ 2 }C=C{ (CH_{ 3 }) }_{ 2 }+{(CH_3)}_2CHC(CH_3)=CH_2$

2,3-dimethylbut-2-ene and 2,3-dimethylbut-1-ene are formed in which 2,3-dimethylbut-2-ene is major product.

The ionization constant of phenol is more than that of ethanol because:

0%
phenoxide ion is a stronger base than ethoxide ion.
0%
phenoxide ion is stabilized by resonance.
0%
ethoxide ion is stabilized by resonance.
0%
phenoxide ion is aromatic while ethoxide ion is aliphatic.

CBSE Questions for Class 12 Medical Chemistry Alcohols, Phenols And Ethers Quiz 4 - MCQExams.com

0:0:1

Practice Class 12 Medical Chemistry Quiz Questions and Answers

CBSE Questions for Class 12 Medical Chemistry Alcohols, Phenols And Ethers Quiz 4 - MCQExams.com

0:0:1

Practice Class 12 Medical Chemistry Quiz Questions and Answers

Support mcqexams.com by disabling your adblocker.