The major product of the following reaction is : $${\rm{C}}{{\rm{H}}_3}{\rm{CH = CHC}}{{\rm{O}}_2}{\rm{CH_3 }}\buildrel {LiAl{H_4}} \over \longrightarrow $$

LiAlH4 reduces esters to alcohols but does not reduce C = C. $${\rm{C}}{{\rm{H}}_3}{\rm{CH = CHC}}{{\rm{O}}_2}{\rm{CH_3 }}\buildrel {LiAl{H_4}} \over \longrightarrow $$ CH3CH = CHCH2OH + CH3OH

Alcohols, Phenols and Ethers Questions — JEE Chemistry

Q1

Match with $$ value)

List - I		List - II
(A)	Ethanol	(I)	10.0
(B)	Phenol	(II)	15.9
(C)	m-Nitrophenol	(III)	7.1
(D)	p-Nitrophenol	(IV)	8.3

A A-I, B-II, C-III, D-IV

B A-IV, B-I, C-II, D-III

C A-II, B-I, C-IV, D-III

D A-III, B-IV, C-I, D-II

Correct Answer

Option C

Solution

\begin{aligned} & \text{ Ethanol } \rightarrow 15.9 \\ & \text{ Phenol } \rightarrow 10 \\ & \text{ M-Nitrophenol } \rightarrow 8.3 \\ & \text{ P-Nitrophenol } \rightarrow 7.1 \end{aligned}

Q2

Bouveault-Blanc reduction reaction involves :

A Reduction of an acyl halide with H2/Pd.

B Reduction of an ester with Na/C2H5OH.

C Reduction of a carbonyl compound with Na/Hg and HCl.

D Reduction of an anhydride with LiAlH4.

Correct Answer

Option B

Solution

Bourveault–Blanc reduction involves the reduction of esters to primary alcohols in the presence of sodium and alcohol.

Q3

The major product of the following reaction is :

{\rm{C}}{{\rm{H}}_3}{\rm{CH = CHC}}{{\rm{O}}_2}{\rm{CH_3 }}\overset{{LiAl{H_4}}}\longrightarrow

A CH3CH2CH2CHO

B CH3CH2CH2CO2CH3

C CH3CH = CHCH2OH

D CH3CH2CH2CH2OH

Correct Answer

Option C

Solution

LiAlH4 reduces esters to alcohols but does not reduce C = C.

{\rm{C}}{{\rm{H}}_3}{\rm{CH = CHC}}{{\rm{O}}_2}{\rm{CH_3 }}\overset{{LiAl{H_4}}}\longrightarrow

CH3CH = CHCH2OH + CH3OH

Q4

During dehydration of alcohols to alkenes by heating with conc. H2SO4 the initiation step is

A formation of carbocation

B elimination of water

C formation of an ester

D protonation of alcohol molecule

Correct Answer

Option D

Solution

The dehydration of alcohol to form alkene occurs in following three step. Step

(1)

is initiation step.

Q5

Acid catalyzed hydration of alkenes except ethene leads to the formation of

A primary alcohol

B secondary or tertiary alcohol

C mixture of primary and secondary alcohols

D mixture of secondary and tertiary alcohols

Correct Answer

Option D

Solution

Water adds directly to the more reactive alkene in presence of a strongly acidic catalyst forming alcohols.

Addition occurs according to Markonikov's rule.

Q6

Given below are two statements : Statement (I) : p-nitrophenol is more acidic than m-nitrophenol and o-nitrophenol. Statement (II) : Ethanol will give immediate turbidity with Lucas reagent. In the light of the above statements, choose the correct answer from the options given below :

A Statement I is true but Statement II is false

B Both Statement I and Statement II are true

C Both Statement I and Statement II are false

D Statement I is false but Statement II is true

Correct Answer

Option A

Solution

Acidic strength Ethanol give lucas test after long time Statement (I) $\rightarrow$ correct Statement (II) $\rightarrow$ incorrect

Q7

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R: Assertion A: Alcohols react both as nucleophiles and electrophiles. Reason R: Alcohols react with active metals such as sodium, potassium and aluminum to yield corresponding alkoxides and liberate hydrogen. In the light of the above statements, choose the correct answer from the options given below:

A

A

is false but

R

is true.

B Both

A

and

R

are true but

R

is NOT the correct explanation of

A

.

C Both

A

and

R

are true and

R

is the correct explanation of

A

.

D

A

is true but

R

is false.

Correct Answer

Option B

Solution

Assertion A is that alcohols can act as both nucleophiles and electrophiles.

This is indeed true.

Alcohols can act as nucleophiles because they have a polar O-H bond; the oxygen atom has a pair of nonbonding electrons that can be donated to electrophiles.

For example, in the presence of a strong acid such as hydrochloric acid, the lone pair on the oxygen can attack the positively charged hydrogen atom to form an oxonium ion (

R-OH_2^+

), which then acts as a good leaving group in substitution reactions.

Alcohols can also behave as electrophiles.

An example of an alcohol acting as an electrophile is when it reacts with a strong base, such as sodium hydride (NaH), to undergo deprotonation forming an alkoxide ion (

R-O^-

).

The alkoxide ion is a strong nucleophile, but the original alcohol molecule in the presence of a base acts as an electrophile due to the acidity of the hydroxyl hydrogen.

Reason R posits that alcohols react with active metals such as sodium, potassium and aluminum to yield corresponding alkoxides and liberate hydrogen.

This is also true.

When alcohols react with active metals, the alcohol acts as an acid, donating a hydrogen ion (

H^+

) to form hydrogen gas (

H_2

), while the remaining alkoxide ion (

R-O^-

) bonds with the metal cation (

M^+

, where M is an active metal like sodium) to form the alkoxide salt (

MOR

).

Now, considering the above explanations, the relationship between Assertion A and Reason R needs to be evaluated: While both Assertion A and Reason R are indeed true, Reason R is not the correct explanation of Assertion A.

Reason R describes a reaction (alcohol with active metal) where the alcohol functions only as an acid (not as a nucleophile or an electrophile).

Hence, Reason R does not explain how alcohols can act as both nucleophiles and electrophiles, which is what Assertion A states.

Therefore, the correct answer is: Option B : Both

A

and

R

are true but

R

is NOT the correct explanation of

A

.

Q8

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R: Assertion A:

\mathrm{pK}_{\mathrm{a}}

value of phenol is 10.0 while that of ethanol is 15.9 . Reason R: Ethanol is stronger acid than phenol. In the light of the above statements, choose the correct answer from the options given below:

A A is false but R is true.

B Both

A

and

R

are true but

R

is NOT the correct explanation of

A

.

C Both

\mathrm{A}

and

\mathrm{R}

are true and

\mathrm{R}

is the correct explanation of

\mathrm{A}

.

D

A

is true but

R

is false.

Correct Answer

Option D

Solution

Phenol is more acidic than ethanol because conjugate base of phenoxide is more stable than ethoxide.

Q9

Phenol treated with chloroform in presence of sodium hydroxide, which further hydrolyzed in presence of an acid results

A Salicylic acid

B Benzene-1,2-diol

C 2-Hydroxybenzaldehyde

D Benzene-1,3-diol

Correct Answer

Option C

Solution

It is Reimer Tiemann Reaction

Q10

Given below are two statements : Statement I : Dimethyl ether is completely soluble in water. However, diethyl ether is soluble in water to a very small extent. Statement II : Sodium metal can be used to dry diethyl ether and not ethyl alcohol. In the light of given statements. choose the correct answer from the options given below

A Statement I is false but Statement II are true

B Statement I is true but Statement II is false

C Both Statement I and Statement II are true

D Both Statement I and Statement II are False

Correct Answer

Option C

Solution

St-I - St-I is correct because both given ether are soluble in water $\rightarrow$ Di ethyl ether and butan-1-ol are miscible to almost same extent i.e., 7.5 and 9 gm per 100 ml water due to H -bonding St-II : - St.

II is also correct because sodium metal is not used with ethyl alcohol as $\mathrm{H}_2$ gas release with ethyl a below