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All questions of Alcohol, Phenol and Ethers for NEET Exam
Fermentation of Glucose to alcohol undergoes in presence of :- a)ZnO
- b)Cr2O3
- c)Invertase
- d)Zymase
Correct answer is option 'D'. Can you explain this answer?
Fermentation of Glucose to alcohol undergoes in presence of :
a)
ZnO
b)
Cr2O3
c)
Invertase
d)
Zymase
|
Lavanya Menon answered |
The correct answer is option D
Zymase is an enzyme complex that catalyzes the fermentation of sugar into ethanol and carbon dioxide. It occurs naturally in yeasts. Zymase activity varies among yeast strains. Zymase is also the brand name of the drug pancrelipase.
Zymase is an enzyme complex that catalyzes the fermentation of sugar into ethanol and carbon dioxide. It occurs naturally in yeasts. Zymase activity varies among yeast strains. Zymase is also the brand name of the drug pancrelipase.
C2H5OH and CH3OCH3 are:- a)Position isomers
- b)Functional isomers
- c)Chain isomer
- d)Metamers
Correct answer is option 'B'. Can you explain this answer?
C2H5OH and CH3OCH3 are:
a)
Position isomers
b)
Functional isomers
c)
Chain isomer
d)
Metamers
|
Vivek Rana answered |
Alkyl alcohol and ether having same molecular formula ( Here C2H6O) are functional isomers of each other. As both having different functional group first one has -OH & second one has -O- functional group in the same carbon chain respectively .
Which alkene is obtained on dehydration of the following alcohol in the presence of H2SO4 ?
- a)
- b)
- c)
- d) None of the above
Correct answer is option 'B'. Can you explain this answer?
Which alkene is obtained on dehydration of the following alcohol in the presence of H2SO4 ?
a)
b)
c)
d)
None of the above
|
Mohit Rajpoot answered |
Carbonium ion formed in 1st step undergoes rearrangement to give tert. carbonium ion since tert-carbonium ions are more stable than secondary one.
Phenol is acidic due to resonance stabilization of its conjugate base :- a)O-H
- b)Benzyl alcohol
- c)Alkoxide ion
- d)Phenoxide ion
Correct answer is option 'D'. Can you explain this answer?
Phenol is acidic due to resonance stabilization of its conjugate base :
a)
O-H
b)
Benzyl alcohol
c)
Alkoxide ion
d)
Phenoxide ion
|
|
Rishika Patel answered |
Polarity of Phenol
Phenol, also known as benzenol or carbolic acid, is an aromatic compound that consists of a benzene ring bonded to a hydroxyl group (-OH). The presence of the hydroxyl group makes phenol a polar molecule because oxygen is more electronegative than carbon and hydrogen.
Acidity of Phenol
Phenol is considered an acid because it can donate a proton (H+) and form a conjugate base. The acidity of phenol is attributed to resonance stabilization of its conjugate base, the phenoxide ion.
Resonance Stabilization of Phenoxide Ion
When phenol loses a proton, it forms the phenoxide ion (C6H5O-). The phenoxide ion is resonance stabilized, which means that the negative charge can be delocalized over the entire ring system through resonance structures.
Resonance Structures of Phenoxide Ion
The resonance structures of the phenoxide ion can be represented as follows:
1. In the first resonance structure, the lone pair on the oxygen atom forms a double bond with carbon, while the negative charge is located on the oxygen atom.
2. In the second resonance structure, the lone pair on the oxygen atom forms a double bond with one of the carbon atoms in the ring, while the negative charge is located on that carbon atom.
3. In the third resonance structure, the lone pair on the oxygen atom forms a double bond with another carbon atom in the ring, while the negative charge is located on that carbon atom.
The resonance structures demonstrate that the negative charge of the phenoxide ion is delocalized over the entire ring system, resulting in stability.
Comparison with Other Options
a) O-H: The O-H bond in phenol is the source of acidity, but it does not explain the resonance stabilization of the conjugate base.
b) Benzyl alcohol: While benzyl alcohol also has an -OH group, it lacks the aromatic ring required for resonance stabilization of the conjugate base.
c) Alkoxide ion: Alkoxide ions are formed when an alcohol loses a proton, but they do not have the same resonance stabilization as the phenoxide ion.
Conclusion
The correct answer is option 'D' (Phenoxide ion) because the resonance stabilization of the phenoxide ion is responsible for the acidity of phenol. The delocalization of the negative charge over the aromatic ring system increases the stability of the conjugate base, making phenol acidic.
Phenol, also known as benzenol or carbolic acid, is an aromatic compound that consists of a benzene ring bonded to a hydroxyl group (-OH). The presence of the hydroxyl group makes phenol a polar molecule because oxygen is more electronegative than carbon and hydrogen.
Acidity of Phenol
Phenol is considered an acid because it can donate a proton (H+) and form a conjugate base. The acidity of phenol is attributed to resonance stabilization of its conjugate base, the phenoxide ion.
Resonance Stabilization of Phenoxide Ion
When phenol loses a proton, it forms the phenoxide ion (C6H5O-). The phenoxide ion is resonance stabilized, which means that the negative charge can be delocalized over the entire ring system through resonance structures.
Resonance Structures of Phenoxide Ion
The resonance structures of the phenoxide ion can be represented as follows:
1. In the first resonance structure, the lone pair on the oxygen atom forms a double bond with carbon, while the negative charge is located on the oxygen atom.
2. In the second resonance structure, the lone pair on the oxygen atom forms a double bond with one of the carbon atoms in the ring, while the negative charge is located on that carbon atom.
3. In the third resonance structure, the lone pair on the oxygen atom forms a double bond with another carbon atom in the ring, while the negative charge is located on that carbon atom.
The resonance structures demonstrate that the negative charge of the phenoxide ion is delocalized over the entire ring system, resulting in stability.
Comparison with Other Options
a) O-H: The O-H bond in phenol is the source of acidity, but it does not explain the resonance stabilization of the conjugate base.
b) Benzyl alcohol: While benzyl alcohol also has an -OH group, it lacks the aromatic ring required for resonance stabilization of the conjugate base.
c) Alkoxide ion: Alkoxide ions are formed when an alcohol loses a proton, but they do not have the same resonance stabilization as the phenoxide ion.
Conclusion
The correct answer is option 'D' (Phenoxide ion) because the resonance stabilization of the phenoxide ion is responsible for the acidity of phenol. The delocalization of the negative charge over the aromatic ring system increases the stability of the conjugate base, making phenol acidic.
The process of converting alkyl halides into alcohols involves_____________.- a)rearrangement reaction
- b)substitution reaction
- c)dehydrohalogenation reaction
- d)addition reaction
Correct answer is option 'B'. Can you explain this answer?
The process of converting alkyl halides into alcohols involves_____________.
a)
rearrangement reaction
b)
substitution reaction
c)
dehydrohalogenation reaction
d)
addition reaction
|
Gaurav Kumar answered |
Converstion of alcohol to alkyl halide is via substitution reaction.
Ethers are :- a)Basic
- b)Amphoteric substances
- c)Acidic
- d)Neutral
Correct answer is option 'A'. Can you explain this answer?
Ethers are :
a)
Basic
b)
Amphoteric substances
c)
Acidic
d)
Neutral
|
|
Sandeep Kumar Chaudhary answered |
O
HAS LONE PAIR IN ETHER SO IT CAN ACCEPT H+.
SO IT IS BEHAVES AS BASE
HAS LONE PAIR IN ETHER SO IT CAN ACCEPT H+.
SO IT IS BEHAVES AS BASE
When aryl halide is heated with 6-8% NaOH solution ,at 623 K under 300 atm pressure we get:- a)Phenol
- b)Benzyl ether
- c)Ethyl alcohol
- d)Cumene
Correct answer is option 'A'. Can you explain this answer?
When aryl halide is heated with 6-8% NaOH solution ,at 623 K under 300 atm pressure we get:
a)
Phenol
b)
Benzyl ether
c)
Ethyl alcohol
d)
Cumene
|
Divey Sethi answered |
The correct answer is Option A.
The aryl halide is heated with 6-8%. NaOH solution at 623K under 300 atm pressure 1) it gives sodium phenoxide 2) sodium phenoxide treated with HCl(acidification) then it gives phenol.
The aryl halide is heated with 6-8%. NaOH solution at 623K under 300 atm pressure 1) it gives sodium phenoxide 2) sodium phenoxide treated with HCl(acidification) then it gives phenol.
What is the product formed when excess of ethanol reacts with concentrated sulphuric acid at 383 K and then the temperature of reaction mixture is increased to 443 K?- a)Ethene
- b)Ethyl hydrogen sulphate
- c)Ethyl chloride
- d)Ethoxy ethane
Correct answer is 'A'. Can you explain this answer?
What is the product formed when excess of ethanol reacts with concentrated sulphuric acid at 383 K and then the temperature of reaction mixture is increased to 443 K?
a)
Ethene
b)
Ethyl hydrogen sulphate
c)
Ethyl chloride
d)
Ethoxy ethane
|
EduRev Support answered |
Nitration of anisole gives majorly:- a)Nitroanisole
- b)para-Nitroanisole
- c)ortho-Nitroanisole
- d)meta-Nitroanisole
Correct answer is option 'B'. Can you explain this answer?
Nitration of anisole gives majorly:
a)
Nitroanisole
b)
para-Nitroanisole
c)
ortho-Nitroanisole
d)
meta-Nitroanisole
|
Prasenjit Malik answered |
When anisole is nitrated with a mixture of conc HNO3 and H2SO4 it gives a mixture of ortho-Nitroanisole and para-Nitroanisole (major) products.
Identify the alcohol or phenol from the following which is most soluble in water.
- a)CH3– OH
- b)CH(CH3)2 CH2O-H
- c)CH3(CH2)2CH2OH
- d)C6H5OH
Correct answer is option 'A'. Can you explain this answer?
Identify the alcohol or phenol from the following which is most soluble in water.
a)
CH3– OH
b)
CH(CH3)2 CH2O-H
c)
CH3(CH2)2CH2OH
d)
C6H5OH
|
Aryan answered |
As...the ...linear chain in alcohol increase ...the solubility decrease .....due to ....staeric + vanderwall force inreacse ...
Identify the alcohol or phenol having a stronger acidic nature from the following.- a)CH3CH2OH
- b)C6H5OH
- c)CH3CHOHCH2CH3
- d)CH3CH2CH2CH2OH
Correct answer is option 'B'. Can you explain this answer?
Identify the alcohol or phenol having a stronger acidic nature from the following.
a)
CH3CH2OH
b)
C6H5OH
c)
CH3CHOHCH2CH3
d)
CH3CH2CH2CH2OH
|
|
Mohit Rajpoot answered |
- Phenol (C₆H₅OH) is more acidic than typical alcohols.
- This is due to the resonance stabilization of the phenoxide ion formed when phenol loses a hydrogen ion (H⁺).
- The negative charge on the oxygen atom in phenoxide ion is delocalized over the aromatic ring, increasing stability and acidity.
- In contrast, alcohols like ethanol (CH₃CH₂OH) do not have such resonance stabilization, making them less acidic.
- Therefore, phenol is the strongest acid among the given options.
- This is due to the resonance stabilization of the phenoxide ion formed when phenol loses a hydrogen ion (H⁺).
- The negative charge on the oxygen atom in phenoxide ion is delocalized over the aromatic ring, increasing stability and acidity.
- In contrast, alcohols like ethanol (CH₃CH₂OH) do not have such resonance stabilization, making them less acidic.
- Therefore, phenol is the strongest acid among the given options.
Which of the following statement is correct?- a)The -OH group in phenol is meta directing.
- b)The electron releasing groups increase the acidic character of phenols.
- c)Phenols are less acidic than aromatic alcohols.
- d)Boiling point of phenol is higher than that of toluene of comparable molecular mass.
Correct answer is option 'D'. Can you explain this answer?
Which of the following statement is correct?
a)
The -OH group in phenol is meta directing.
b)
The electron releasing groups increase the acidic character of phenols.
c)
Phenols are less acidic than aromatic alcohols.
d)
Boiling point of phenol is higher than that of toluene of comparable molecular mass.
|
|
Divey Sethi answered |
The correct answer is Option D.
Phenols have higher boiling point than toluene due to the presence of intermolecular hydrogen bonding in phenols. The formation of hydrogen bonds increases the intermolecular force of attraction between the phenol molecules and thereby increases its boiling point.
Can you explain the answer of this question below:The acidity of phenols is due to
- A:
Oxidation process
- B:
Resonance stabilization of its ions.
- C:
Hybridisation
- D:
Presence of O-H group
The answer is b.
The acidity of phenols is due to
Oxidation process
Resonance stabilization of its ions.
Hybridisation
Presence of O-H group
|
Rahul Bansal answered |
The acidity of phenols is due to its ability to lose hydrogen ion to form phenoxide ions. In a phenol molecule, the sp2hybridised carbon atom of benzene ring attached directly to the hydroxyl group acts as an electron withdrawing group. This sp2 hybridized carbon atom of benzene ring attached directly to the hydroxyl group has higher electronegativity in comparison to hydroxyl group. Due to the higher electronegativity of this carbon atom in comparison to the hydroxyl group attached, electron density decreases on oxygen atom. The decrease in electron density increases the polarity of O-H bond and results in the increase in ionization of phenols. Thus, the phenoxide ion is formed. The phenoxide ion formed is stabilized by the delocalization of negative charge due to the resonance in benzene ring. Phenoxide ion has greater stability than phenols, as in case of phenol charge separation takes place during resonance.The resonance structures of phenoxide ions explain the delocalization of negative charge. In case of substituted phenols, acidity of phenols increases in the presence of electron withdrawing group. This is due to the stability of the phenoxide ion generated. The acidity of phenols further increases if these groups are attached at ortho and para positions. This is due to the fact that the negative charge in phenoxide ion is mainly delocalized at ortho and para positions of the attached benzene ring. On the other hand, the acidity of phenols decreases in presence of electron donating groups as they prohibit the formation of phenoxide ion.
Which of the following will not form a yellow precipitate on heating with an alkaline solution of iodine? [2004]- a) CH3CH(OH)CH3
- b)CH3CH2CH(OH)CH3
- c)CH3OH
- d)CH3CH2OH
Correct answer is option 'C'. Can you explain this answer?
Which of the following will not form a yellow precipitate on heating with an alkaline solution of iodine? [2004]
a)
CH3CH(OH)CH3
b)
CH3CH2CH(OH)CH3
c)
CH3OH
d)
CH3CH2OH
|
Prasenjit Pillai answered |
CH3OH does not have -CH(OH)CH3 grouping hence it will not form yellow precipitate with an alkaline solution of iodine (haloform reaction).
What is the IUPAC name of di-isopropyl ethera)Salicyaldehydeb)Ethyl acetatec)Iso propoxy propaned)Ethyl methyl etherCorrect answer is option 'C'. Can you explain this answer?
|
Shreya Gupta answered |
2-Iso propoxy propane
- Molecular Formula: C6H14O
- Average mass: 102.174797 Da
- Monoisotopic mass: 102.104462 Da
We can obtain picric acid from phenol by:- a)Sulphonation of phenol
- b)By Reimer Tiemann reaction
- c)Nitration of phenol
- d)Halogenation of phenol
Correct answer is option 'C'. Can you explain this answer?
We can obtain picric acid from phenol by:
a)
Sulphonation of phenol
b)
By Reimer Tiemann reaction
c)
Nitration of phenol
d)
Halogenation of phenol
|
|
Shreya Gupta answered |
Phenol heated with sulphuric acid gives phenol disulphonic acid, which further on reaction with nitric acid forms picric acid (2,4,6-trinitrophenol).
IUPAC name of m-cresol is ___________.- a)3-methylphenol
- b)3-chlorophenol
- c) 3-methoxyphenol
- d)benzene-1,3-diol
Correct answer is option 'A'. Can you explain this answer?
IUPAC name of m-cresol is ___________.
a)
3-methylphenol
b)
3-chlorophenol
c)
3-methoxyphenol
d)
benzene-1,3-diol
|
Preeti Iyer answered |
Meta-Cresol, also 3-methylphenol, is an organic compound with the formula CH3C6H4(OH). It is a colourless, viscous liquid that is used as an intermediate in the production of other chemicals. It is a derivative of phenol and is an isomer of p-cresol and o-cresol.
Which catalyst is used in Fischer-Speier esterification?
- a)Concentrated H2SO4
- b)Dry HCl gas
- c)Concentrated HNO3
- d)Pyridine
Correct answer is option 'A'. Can you explain this answer?
Which catalyst is used in Fischer-Speier esterification?
a)
Concentrated H2SO4
b)
Dry HCl gas
c)
Concentrated HNO3
d)
Pyridine
|
|
Pooja Mehta answered |
Esterification is a relatively slow process at room temperature and does not proceed to completion. Concentrated sulfuric acid is used as a catalyst, and has a dual role: Speeds up the reaction. Acts as a dehydrating agent, forcing the equilibrium to the right and resulting in a greater yield of ester.
Williamsons synthesis is an example of :- a)Electrophilic substitution
- b)Electrophilic addition
- c)Nucleophilic substitution reaction
- d)Nucleophilic addition
Correct answer is option 'C'. Can you explain this answer?
Williamsons synthesis is an example of :
a)
Electrophilic substitution
b)
Electrophilic addition
c)
Nucleophilic substitution reaction
d)
Nucleophilic addition
|
|
Shreya Gupta answered |
The Williamson ether synthesis is an organic reaction used to convert an alcohol and an alkyl halide to an ether using a base such as NaOH. The mechanism begins with the base abstracting the proton from the alcohol to form an alkoxide intermediate. The alkoxide then attacks the alkyl halide in a nucleophilic substi-tution reaction (SN2), which results in the formation of the final ether product and a metal halide by-product.
Phenols do not respond to which of these tests?- a)Schiff’s reagent test
- b)FeCl3 test
- c)Br2 water test
- d)Litmus test
Correct answer is option 'A'. Can you explain this answer?
Phenols do not respond to which of these tests?
a)
Schiff’s reagent test
b)
FeCl3 test
c)
Br2 water test
d)
Litmus test
|
|
Rajeev Saxena answered |
Phenols respond to all the above mentioned tests except Schiff’s reagent test, which is shown by aldehydes.
Phenol is distilled with Zn dust followed by Friedel Crafts alkylation with propyl chloride in the presence of AlCl3 to give a compound (B). (B) is oxidised in the presence of air to form the compound (C). The structural formula of (C) is [NEET Kar. 2013]- a)
- b)
- c)
- d)
Correct answer is option 'C'. Can you explain this answer?
Phenol is distilled with Zn dust followed by Friedel Crafts alkylation with propyl chloride in the presence of AlCl3 to give a compound (B). (B) is oxidised in the presence of air to form the compound (C). The structural formula of (C) is [NEET Kar. 2013]
a)
b)
c)
d)
|
Ashwini Khanna answered |
How many isomers of C5H11 OH will be primary alcohols ? [1992]- a)5
- b)4
- c)2
- d)3.
Correct answer is option 'B'. Can you explain this answer?
How many isomers of C5H11 OH will be primary alcohols ? [1992]
a)
5
b)
4
c)
2
d)
3.
|
Gowri Nair answered |
Four primary alcohols of C5H11OH are possible. These are:
(i) CH3CH2CH2CH2CH2OH
(ii)
(iii)
(iv)
Phenol on treatment with Phthalic anhydride gives:- a)Phenolphthalein
- b)Salicylaldehyde
- c)Phthalic acid
- d)Salicylic acid
Correct answer is option 'A'. Can you explain this answer?
Phenol on treatment with Phthalic anhydride gives:
a)
Phenolphthalein
b)
Salicylaldehyde
c)
Phthalic acid
d)
Salicylic acid
|
Infinity Academy answered |
The correct answer is option A
Phenolphthalein gives pink colour with alkali.
Phenolphthalein gives pink colour with alkali.
Phenol can be distinguished from ethanol by the reactions with _________.
- a)Br2/water
- b)Na
- c)Neutral FeCl3
- d)A and C
Correct answer is option 'D'. Can you explain this answer?
Phenol can be distinguished from ethanol by the reactions with _________.
a)
Br2/water
b)
Na
c)
Neutral FeCl3
d)
A and C
|
Nisha Banerjee answered |
- Phenol can be distinguished from ethanol using Br2/water and Neutral FeCl3.
- Br2/water: Phenol reacts with bromine water to give a white precipitate of 2,4,6-tribromophenol, while ethanol does not react.
- Neutral FeCl3: Phenol forms a violet complex with neutral ferric chloride, whereas ethanol shows no color change.
- Therefore, options A and C are correct for distinguishing phenol from ethanol.
Ethers may be used as solvents because they react only with which of the following reactants?- a)Acids
- b)Bases
- c)Oxidising agent
- d)Reducing agents
Correct answer is option 'A'. Can you explain this answer?
Ethers may be used as solvents because they react only with which of the following reactants?
a)
Acids
b)
Bases
c)
Oxidising agent
d)
Reducing agents
|
|
Geetika Shah answered |
Ethers resist the attack of nucleophiles and bases. However, they are very good solvents in many organic reactions due to their ability to solvate cations by donating the electron pair from oxygen atom. Ethers are generally less reactive and react only with acids.
Isopropyl alcohol on oxidation forms:- a)Acetone
- b)Ether
- c)Acetaldehyde
- d)Methane
Correct answer is option 'A'. Can you explain this answer?
Isopropyl alcohol on oxidation forms:
a)
Acetone
b)
Ether
c)
Acetaldehyde
d)
Methane
|
|
Rahul Bansal answered |
The oxidation of isopropyl alcohol by potassium dichromate (K 2Cr 2O 7) gives acetone, the simplest ketone: Unlike aldehydes, ketones are relatively resistant to further oxidation, so no special precautions are required to isolate them as they form.
To prepare tert-butyl ethyl ether, the reagents required are:
- a)Sodium ethoxide and tert-butyl bromide
- b)Sodium tert butoxide and ethyl bromide
- c)Dimethyl ketone, ethylbromide and sodium
- d)Sodium propoxide and propyl bromide
Correct answer is option 'B'. Can you explain this answer?
To prepare tert-butyl ethyl ether, the reagents required are:
a)
Sodium ethoxide and tert-butyl bromide
b)
Sodium tert butoxide and ethyl bromide
c)
Dimethyl ketone, ethylbromide and sodium
d)
Sodium propoxide and propyl bromide
|
Ayush Joshi answered |
Because 3degree haloalkanes like tert-butyl bromide (option a) give alkenes and not ethers when treated with a strong base like sodium ethoxide. So the exact answer is (b).
Which of the following compounds will react with sodium hydroxide solution in water?- a)C6H5OH
- b)C6H5CH2OH
- c)(CH3)3COH
- d)C2H5OH
Correct answer is option 'A'. Can you explain this answer?
Which of the following compounds will react with sodium hydroxide solution in water?
a)
C6H5OH
b)
C6H5CH2OH
c)
(CH3)3COH
d)
C2H5OH
|
|
Vijay Bansal answered |
When phenol reacts with sodium hydroxide solution it gives a colourless solution containing sodium phenoxide.
In this reaction, the hydrogen ion has been removed by the strongly basic hydroxide ion in the sodium hydroxide solution.
How many alcohols with molecular formula C4H10O are chiral in nature?a)2b)1c)4d)3Correct answer is option 'B'. Can you explain this answer?
|
Mansi Nair answered |
Here, again carbon is not chiral in nature.
So, only one alcohol is chiral in nature
So, only one alcohol is chiral in nature
An organic compound X is oxidised by using acidified K2Cr2O7. The product obtained reacts with Phenyl hydrazine but does not answer silver mirror test. The possible structure of X is- a)CH3CH2OH
- b)CH3CHO
- c)(CH3)2CHOH
- d)None of the these
Correct answer is option 'C'. Can you explain this answer?
An organic compound X is oxidised by using acidified K2Cr2O7. The product obtained reacts with Phenyl hydrazine but does not answer silver mirror test. The possible structure of X is
a)
CH3CH2OH
b)
CH3CHO
c)
(CH3)2CHOH
d)
None of the these
|
|
Baby Ghosh answered |
Yup...it will be propan-2-ol..by oxidation it..it will convert into acetone and it reacts with phenyl hydrazine,it produces acetone phenyl hydrazone and there is no aldehyde grp in acetone. so it doesn't react in silver mirror test means with tollen's reagent..
One Integer Value Correct TypeDirection (Q. Nos. 19-22) This section contains 4 questions. When worked out will result in an integer from 0 to 9 (both inclusive).In the following reaction,
Q. How many different diols are formed as a result of nucleophilic addition reaction?
Correct answer is '3'. Can you explain this answer?
One Integer Value Correct Type
Direction (Q. Nos. 19-22) This section contains 4 questions. When worked out will result in an integer from 0 to 9 (both inclusive).
In the following reaction,
Q.
How many different diols are formed as a result of nucleophilic addition reaction?
|
|
Ritu Singh answered |
What is the correct structure for the major compound produced by the following reaction sequence?
- a)
- b)
- c)
- d)
Correct answer is option 'B'. Can you explain this answer?
What is the correct structure for the major compound produced by the following reaction sequence?
a)
b)
c)
d)
|
Gunjan Lakhani answered |
Reaction involves rearrangement of carbocation
Which of the following compounds will form hydrocarbon on reaction with Grignard reagent ?- a)CH2CHO
- b)CH3COCH3
- c) CH3CH2OH
- d)CH3CO2CH3
Correct answer is option 'C'. Can you explain this answer?
Which of the following compounds will form hydrocarbon on reaction with Grignard reagent ?
a)
CH2CHO
b)
CH3COCH3
c)
CH3CH2OH
d)
CH3CO2CH3
|
Chirag Joshi answered |
Formation of Hydrocarbon from Grignard Reagent
Grignard reagent is a very strong nucleophile and a powerful reducing agent. It reacts with various types of carbonyl compounds to form alcohols, which can further react to form hydrocarbons. However, not all carbonyl compounds can form hydrocarbons on reaction with Grignard reagent. Let's discuss the given options:
a) CH2CHO: This is formaldehyde, which has a carbonyl group. It can react with Grignard reagent to form a primary alcohol, but it cannot form a hydrocarbon.
b) CH3COCH3: This is acetone, which also has a carbonyl group. It can react with Grignard reagent to form a secondary alcohol, but it cannot form a hydrocarbon.
c) CH3CH2OH: This is ethanol, which has a hydroxyl group. It can react with Grignard reagent to form a secondary alcohol, which can further react to form an alkene (hydrocarbon).
d) CH3CO2CH3: This is ethyl acetate, which has an ester group. It can react with Grignard reagent to form a tertiary alcohol, but it cannot form a hydrocarbon.
Therefore, the correct answer is option 'C' (CH3CH2OH).
Grignard reagent is a very strong nucleophile and a powerful reducing agent. It reacts with various types of carbonyl compounds to form alcohols, which can further react to form hydrocarbons. However, not all carbonyl compounds can form hydrocarbons on reaction with Grignard reagent. Let's discuss the given options:
a) CH2CHO: This is formaldehyde, which has a carbonyl group. It can react with Grignard reagent to form a primary alcohol, but it cannot form a hydrocarbon.
b) CH3COCH3: This is acetone, which also has a carbonyl group. It can react with Grignard reagent to form a secondary alcohol, but it cannot form a hydrocarbon.
c) CH3CH2OH: This is ethanol, which has a hydroxyl group. It can react with Grignard reagent to form a secondary alcohol, which can further react to form an alkene (hydrocarbon).
d) CH3CO2CH3: This is ethyl acetate, which has an ester group. It can react with Grignard reagent to form a tertiary alcohol, but it cannot form a hydrocarbon.
Therefore, the correct answer is option 'C' (CH3CH2OH).
Which one of the following compounds will be most readily attacked by an electrophile ?[1989]- a)Chlorobenzene
- b)Benzene
- c)Phenol
- d)Toluene
Correct answer is option 'C'. Can you explain this answer?
Which one of the following compounds will be most readily attacked by an electrophile ?[1989]
a)
Chlorobenzene
b)
Benzene
c)
Phenol
d)
Toluene
|
Abhijeet Goyal answered |
Due to strong electron-donating effect of the OH group, the electron density in phenol is much higher than that in toluene, benzene and chlorobenzene and hence phenol is readily attacked by the electrophile.
When glycerol is treated with excess of HI, it produces: [2010]- a)glycerol triiodide
- b)2–iodopropane
- c)allyl iodide
- d)pr open e
Correct answer is option 'B'. Can you explain this answer?
When glycerol is treated with excess of HI, it produces: [2010]
a)
glycerol triiodide
b)
2–iodopropane
c)
allyl iodide
d)
pr open e
|
Nilanjan Chakraborty answered |
Glycerol when treated with excess HI produces 2–iodopropane
∴ Correct choice : (b)
Which of the following is obtained as a major product in Friedel-Craft’s alkylation of phenol ?
- a)
- b)
- c)
- d)
Correct answer is option 'A'. Can you explain this answer?
Which of the following is obtained as a major product in Friedel-Craft’s alkylation of phenol ?
a)
b)
c)
d)
|
Sushil Kumar answered |
The correct answer is option A
P-methyl phenol is the major product.
P-methyl phenol is the major product.
Lucas test is associated with
- a)Phenols
- b)Aldehydes
- c)Carboxylic acid
- d)Alcohols
Correct answer is option 'D'. Can you explain this answer?
Lucas test is associated with
a)
Phenols
b)
Aldehydes
c)
Carboxylic acid
d)
Alcohols
|
|
Vijay Bansal answered |
- The Lucas test is used with alcohols to tell the difference between primary, secondary, and tertiary alcohols based on how they react with a special mixture known as Lucas reagent, which is made up of concentrated hydrochloric acid and zinc chloride.
- Tertiary alcohols react right away, creating a cloudy solution.
- Secondary alcohols take about 5 to 10 minutes to react, also forming a cloudy solution.
- Primary alcohols show very little to no reaction at room temperature.
- The test works because it leads to the creation of alkyl chloride, which does not mix well with water, making it easier to see the reactions.
When phenol is treated with excess bromine water. It gives [1992]- a)m-Bromophenol
- b)o-and p-Bromophenols
- c)2,4-Dibromophenol
- d)2,4, 6-Tribromophenol.
Correct answer is option 'D'. Can you explain this answer?
When phenol is treated with excess bromine water. It gives [1992]
a)
m-Bromophenol
b)
o-and p-Bromophenols
c)
2,4-Dibromophenol
d)
2,4, 6-Tribromophenol.
|
|
Soumya Nair answered |
With Br2 water, phenol gives 2, 4, 6-tribromophenol.
What is formed when a primary alcohol undergoes catalytic dehydrogenation ? [1993]- a)Aldeh yde
- b)Ketone
- c)Alkene
- d)Acid
Correct answer is option 'A'. Can you explain this answer?
What is formed when a primary alcohol undergoes catalytic dehydrogenation ? [1993]
a)
Aldeh yde
b)
Ketone
c)
Alkene
d)
Acid
|
sankalp raj answered |
In hydrogenation the primary alcohol convert into aldehyde but how dehydrogenation? cause this...
The stablest among the following is [1994]- a)CH3CH(OH)2
- b)ClCH2CH(OH)2
- c)(CH3)2 C (OH)2
- d)CCl3 CH (OH)2.
Correct answer is option 'D'. Can you explain this answer?
The stablest among the following is [1994]
a)
CH3CH(OH)2
b)
ClCH2CH(OH)2
c)
(CH3)2 C (OH)2
d)
CCl3 CH (OH)2.
|
Soumya Ahuja answered |
Due to –I-effect of the three C–Cl-bonding between CI and C-atom of the OH group, CCl3 CH (OH)2 is most stable.
What is the product of the reaction of methyl cyclohexene with B2H6 in THF followed by the oxidation with alkaline H2O2?
- a)Both I and IV
- b)Only II
- c)Both III and IV
- d)Both II and II
Correct answer is option 'D'. Can you explain this answer?
What is the product of the reaction of methyl cyclohexene with B2H6 in THF followed by the oxidation with alkaline H2O2?
a)
Both I and IV
b)
Only II
c)
Both III and IV
d)
Both II and II
|
|
Shail Chawla answered |
In hydroboration oxidation reaction anti-Markownikoff addition of water takes place. Also both "H" and "OH" groups are attached from same side.
If 3, 3-dimethyl-2, 4-pentanedione is treated with a Grignard reagent consisting of mixture of CH3MgBr and C2H5MgBr and finally hydrolysing product with dilute H2SO4 results in the formation of how many different diols?
Correct answer is '6'. Can you explain this answer?
If 3, 3-dimethyl-2, 4-pentanedione is treated with a Grignard reagent consisting of mixture of CH3MgBr and C2H5MgBr and finally hydrolysing product with dilute H2SO4 results in the formation of how many different diols?
|
|
Om Desai answered |
(II) has two chiral carbon but symmetrical, hence, three stereoisomers.
(III) has only one chiral carbon hence, two stereoisomers (pair of enantiomers).
Phenol is less acidic than ______________.
- a)o – nitrophenol
- b)o – methoxyphenol
- c)ethanol
- d)o – methylphenol
Correct answer is option 'A'. Can you explain this answer?
Phenol is less acidic than ______________.
a)
o – nitrophenol
b)
o – methoxyphenol
c)
ethanol
d)
o – methylphenol
|
Samridhi Bajaj answered |
- Phenol is not as acidic as O-nitrophenol.
- The nitro group is a type of group that pulls electrons away.
- This pulling of electrons reduces the electron density on the benzene ring and spreads out the negative charge of the phenoxide ion.
- Because of this, the acidity increases, making O-nitrophenol more acidic than phenol.
- In contrast, the methoxy group is a group that releases electrons.
- This release of electrons raises the electron density on the benzene ring and does not spread out the negative charge of the phenoxide ion.
- As a result, p-methoxyphenol is less acidic than phenol.
- Additionally, alcohols, such as 2-methylpropanol and 2,2-dimethylpentanol, are considered neutral.
Which of the following compounds can be used as antifreeze in automobile radiators ? [2012 M]- a)Methyl alcohol
- b)Glycol
- c)Nitrophenol
- d)Ethyl alcohol
Correct answer is option 'B'. Can you explain this answer?
Which of the following compounds can be used as antifreeze in automobile radiators ? [2012 M]
a)
Methyl alcohol
b)
Glycol
c)
Nitrophenol
d)
Ethyl alcohol
|
Ishaan Menon answered |
Glycol is used as an antifreeze in automobiles.
Which of the following is correct ? [2001]- a)On reduction of any aldehyde, secondary alcohol is formed
- b)Reaction of vegetable oil with H2SO4 gives glycerine
- c)Sucrose on reaction with NaCl gives invert sugar
- d)Alcoholic iodine gives iodoform with NaOH
Correct answer is option 'D'. Can you explain this answer?
Which of the following is correct ? [2001]
a)
On reduction of any aldehyde, secondary alcohol is formed
b)
Reaction of vegetable oil with H2SO4 gives glycerine
c)
Sucrose on reaction with NaCl gives invert sugar
d)
Alcoholic iodine gives iodoform with NaOH
|
Pankaj Kulkarni answered |
Chapter doubts & questions for Alcohol, Phenol and Ethers - 4 Months Preparation for NEET 2025 is part of NEET exam preparation. The chapters have been prepared according to the NEET exam syllabus. The Chapter doubts & questions, notes, tests & MCQs are made for NEET 2025 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests here.
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