Which of the following characterizes the reactions of aldehydes and ketones? (a) electrophilic addition (b) electrophilic substitution (c) nucleophilic acyl substitution (d) nucleophilic addition; free radical addition

Which of the following characterizes the reactions of aldehydes and ketones?
(a) electrophilic addition
(b) electrophilic substitution
(c) nucleophilic acyl substitution
(d) nucleophilic addition; free radical addition
by

1 Answer

Answer :

nucleophilic addition; free radical addition
by

Related questions

Why do aldehydes undergo nucleophilic addition reactions while esters undergo nucleophilic acyl substitution reactions? (a) The carbonyl carbon of an ester is more electrophilic than that of an aldehyde. (b) Aldehydes are more sterically hindered than esters. (c) Once the nucleophile adds to an aldehyde, the tetrahedral intermediate is too sterically hindered to eliminate one of the attached groups. (d) Once the nucleophile adds to an aldehyde, neither H− nor R− can be eliminated since they are strongly basic

Description : Why do aldehydes undergo nucleophilic addition reactions while esters undergo nucleophilic acyl substitution reactions? (a) The carbonyl carbon of an ester is more electrophilic than that of an aldehyde. (b) ... adds to an aldehyde, neither H− nor R− can be eliminated since they are strongly basic

Last Answer : Once the nucleophile adds to an aldehyde, neither H− nor R− can be eliminated since they are strongly basic

The chlorination of methane to give CCl4 is an example of (a) an electrophilic addition (b) a free-radical substitution (c) a nucleophilic addition (d) an electrophilic substitution

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Last Answer : a free-radical substitution

Which statement about the carbonyl group of ketones and aldehydes is true? I. It can attract nucleophiles. II. It can attract electrophiles. III. It tends to undergo addition reactions. IV. It tends to undergo substitution reactions. (a) I and III (b) II and IV (c) I, II, and III (d) I, III, and IV

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Last Answer : I, II, and III

Alkyl halides undergo (a) Electrophilic substitution reactions (b) Electrophilic addition reactions (c) Nucleophilic substitution reactions (d) Nucleophilic addition reactions

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Benzene reacts with concentrated HNO3 in the presence of concentrated H2SO4 to give nitrobenzene. This reaction is an example of (a) Electrophilic addition (b) Nucleophilic addition (c) Electrophilic substitution (d) Nucleophilic substitution

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Last Answer : Electrophilic substitution

Benzene reacts with concentrated HNO3 in the presence of concentrated H2SO4 to give nitrobenzene. This reaction is an example of (a) Electrophilic addition (b) Nucleophilic addition (c) Electrophilic substitution (d) Nucleophilic substitution

Description : Benzene reacts with concentrated HNO3 in the presence of concentrated H2SO4 to give nitrobenzene. This reaction is an example of (a) Electrophilic addition (b) Nucleophilic addition (c) Electrophilic substitution (d) Nucleophilic substitution

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The characteristic reaction of carboxylic acids is : (a) electrophilic addition (b) electrophilic substitution (c) nucleophilic addition (d) nucleophilic substitution

Description : The characteristic reaction of carboxylic acids is : (a) electrophilic addition (b) electrophilic substitution (c) nucleophilic addition (d) nucleophilic substitution

Last Answer : nucleophilic substitution

Acetone reacts with HCN to form a cyanohydrin. It is an example of (a) Electrophilic addition (b) Electrophilic substitution (c) Nucleophilic addition(d) Nucleophilic substitution

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Last Answer : Nucleophilic addition

Propene reacts with bromine to form 1,2-dibromopropane. This is an example of (a) Nucleophilic addition (b) Electrophilic addition (c) Nucleophilic substitution (d) Electrophilic substitution

Description : Propene reacts with bromine to form 1,2-dibromopropane. This is an example of (a) Nucleophilic addition (b) Electrophilic addition (c) Nucleophilic substitution (d) Electrophilic substitution

Last Answer : Electrophilic addition

Why does benzene undergo electrophilic substitution reactions easily and nucleophilic substitutions with difficulty?

Description : Why does benzene undergo electrophilic substitution reactions easily and nucleophilic substitutions with difficulty?

Last Answer : Ans. Due to the presence of an electron cloud containing 6 pi electrons above and below the plane of the ring, benzene is a source of electrons. Consequently, it attracts ... . As a result, benzene undergoes electrophilic substitution reactions easily and nucleophilic substitution with difficulty.

Esters and amides are most easily made by nucleophilic acyl substitution reactions on : (a) acid anhydrides (b) carboxylates (c) carboxylic acids (d) acid chlorides

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Last Answer : acid chlorides

What purpose does FeCl3 serve in the electrophilic aromatic substitution reaction between chlorine and benzene? (a) It serves as a radical initiator to produce the chlorine radical needed to propagate the chain reaction. (b) It functions by destabilizing the carbocationic intermediate and thereby increases the rate of H+ loss. (c) It serves as a Lewis base catalyst by reacting with Cl2 to generate chloride ions. (d) It serves as a Lewis acid catalyst by reacting with the Cl2 and thereby activates it toward attack by benzene’s π electrons.

Description : What purpose does FeCl3 serve in the electrophilic aromatic substitution reaction between chlorine and benzene? (a) It serves as a radical initiator to produce the chlorine radical needed to propagate the ... by reacting with the Cl2 and thereby activates it toward attack by benzene's π electrons.

Last Answer : It serves as a Lewis acid catalyst by reacting with the Cl2 and thereby activates it toward attack by benzene’s π electrons.

Which of the following is not a correct statement about the electrophilic substitution mechanism of benzene? (a) Benzene functions as a nucleophile. (b) Formation of a carbocation intermediate is the rate-determining step. (c) The carbocation intermediate contains an sp3 hybridized carbon in the ring. (d) The addition product is a frequently observed minor product.

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Last Answer : The addition product is a frequently observed minor product.

Anthracene undergoes electrophilic substitution reactions mainly at (a) C-1 (b) C-2 (c) C-9 (d) C-1 and C-2

Description : Anthracene undergoes electrophilic substitution reactions mainly at (a) C-1 (b) C-2 (c) C-9 (d) C-1 and C-2

Last Answer : C-9

Which of the following compounds reacts least rapidly in electrophilic substitution reactions? (a) Nitrobenzene (b) Phenol (c) Bromobenzene (d) Toluene

Description : Which of the following compounds reacts least rapidly in electrophilic substitution reactions? (a) Nitrobenzene (b) Phenol (c) Bromobenzene (d) Toluene

Last Answer : Nitrobenzene

Which of the reactions between the following pairs of reagents proceeds by a mechanism that may be described as an electrophilic substitution? (a) Benzene + Br2/FeBr3 (b) Propene + Br2 (c) Acetone + NH2NH2 (d) Ethyl bromide + aq KOH

Description : Which of the reactions between the following pairs of reagents proceeds by a mechanism that may be described as an electrophilic substitution? (a) Benzene + Br2/FeBr3 (b) Propene + Br2 (c) Acetone + NH2NH2 (d) Ethyl bromide + aq KOH

Last Answer : Benzene + Br2/FeBr3

In electrophilic aromatic substitution reactions a chlorine substituent __________. (a) is a deactivator and a m-director (b) is a deactivator and an o,p-director (c) is an activator and a m-director (d) is an activator and an o,p-director

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Last Answer : is a deactivator and an o,p-director

Esters can be formed by nucleophilic substitution reactions of : (a) carboxylic acids and alcohols ; acid-catalyzed (b) acid chlorides and alcohols (c) both of the above (d) neither of the above

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Last Answer : both of the above

Why are aldehydes more reactive than ketones ?

Description : Why are aldehydes more reactive than ketones ? 

Last Answer : Ans. It is because of 2 reasons : The carboxyl compounds (both aldehydes & ketones) undergo nucleophilic addition reaction. (i) + I effect : The alkyl group in ketones due to their e- ... its reactivity. (ii) Steric hindrance : Due to steric hindrance in ketones, they are less reactive.

Which of the following statements is NOT correct : (a) Tollens' test is given by both aliphatic and aromatic aldehydes. (b) Fehling's test is given by aliphatic aldehydes. It is not given by aromatic aldehydes. (c) Iodoform test is given by methyl ketones and acetaldehydes. (d) Lucas test is given by both aliphatic and aromatic aldehydes

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Aldehydes can be distinguished from ketones by using (a) Ammoniacal AgNO3 solution (b) Phenylhydrazine (c) Saturated NaHSO3 solution (d) Thionyl chloride

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Last Answer : Ammoniacal AgNO3 solution

Aldehydes undergo oxidation with KMnO4/H+ to give (a) Alcohols (b) Acetals (c) Ketones (d) Acids

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Last Answer : Acids

Which of the following reagents will react readily with both aldehydes and ketones? (a) Grignard reagent (b) Fehling's reagent (c) Tollens' reagent (d) Schiff's reagen

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Last Answer : Grignard reagent

Which action best accounts for the solubility of aldehydes and ketones in water? (a) Polar interactions between solute molecules. (b) H-bonding between solute molecules. (c) Van der waals forces (d) H-bonding between solute and solvent molecules

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Last Answer : H-bonding between solute and solvent molecules

The melting points of aldehydes and ketones tend to : (a) decrease with increasing molecular weight. (b) increase with increasing molecular weight. (c) remain unchanged with increasing molecular weight. (d) be unpredictable due to resonance

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Last Answer : increase with increasing molecular weight.

What property of low-molecular weight aldehydes and ketones accounts for the magnitude of their boiling points? (a) The ability to form strong H-bonds between their molecules. (b) The ability of the carbonyl oxygen to form H-bonds with other carbonyl groups. (c) The ability of the polar carbonyl group to attract other polar molecules. (d) The ability of the carbonyl group to attract electrophiles and form bonds.

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Last Answer : The ability of the polar carbonyl group to attract other polar molecules.

Explain why nucleophilic substitution reactions are not very common in phenols.

Description : Explain why nucleophilic substitution reactions are not very common in phenols.

Last Answer : Explain why nucleophilic substitution reactions are not very common in phenols.

(A) Ethyl chloride is more reactive than vinyl chloride towards nucleophilic substitution reactions. (R) Vinyl chloride is `+I` electron pushing group

Description : (A) Ethyl chloride is more reactive than vinyl chloride towards nucleophilic substitution reactions. (R) Vinyl chloride is `+I` electron pushing group

Last Answer : (A) Ethyl chloride is more reactive than vinyl chloride towards nucleophilic substitution reactions. (R) Vinyl ... A) is incorrect but (R) is correct.

Identify the correct order of reactivity in electrophilic substitution reactions of the following compounds:

Description : Identify the correct order of reactivity in electrophilic substitution reactions of the following compounds:

Last Answer : Identify the correct order of reactivity in electrophilic substitution reactions of the following ... C. `IIgtIgtIIIgtIV` D. `IIgtIIIgtIgtIV`

Identify the correct order of reactivity in electrophilic substitution reactions of the following compounds :

Description : Identify the correct order of reactivity in electrophilic substitution reactions of the following compounds :

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Arrange the following carboxyl compounds in increasing order of their reactivity in nucleophilic addition reactions. Explain with proper reasoning : Benzaldehyde. p-tolualdeyde, p-nitrobenzaldehyde, Acetophenone.

Description : Arrange the following carboxyl compounds in increasing order of their reactivity in nucleophilic addition reactions. Explain with proper reasoning : Benzaldehyde. p-tolualdeyde, p-nitrobenzaldehyde, Acetophenone.

Last Answer : Ans. Acetophenone is a ketone while all others are aldehydes, therefore it is least reactive. In p-tolualdehyde, there is methyl group (CH3 ) at para position w.r.t. to the ... overall order of increasing reactivity : acetophenone < p-tolualdehyde < benzaldehyde < p-nitrobenzaldehyde. 

Which of the following statements correctly describes the general reactivity of alkynes? (a) An alkyne is an electron-rich molecule and therefore reacts as a nucleophile. (b) The σ bonds of alkynes are higher in energy than the bonds and are thus more reactive. (c) Unlike alkenes, alkynes fail to undergo electrophilic addition reactions. (d) Alkynes are generally more reactive than alkenes.

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Last Answer : Alkynes are generally more reactive than alkenes.

Phenol is an ortho-para director because the hydroxyl group : (a) donates electrons that increase electron density at ortho and para positions favoring nucleophilic attack. (b) donates electrons that increase electron density at ortho and para positions favoring electrophilic attack. (c) donates electrons to the ortho and para positions and attracts electrons away from meta positions favoring nucleophilic attack of the ring. (d) donates electrons to the ortho and para positions and attracts electrons away from meta positions favoring electrophilic attack on the ring.

Description : Phenol is an ortho-para director because the hydroxyl group : (a) donates electrons that increase electron density at ortho and para positions favoring nucleophilic attack. (b) donates ... para positions and attracts electrons away from meta positions favoring electrophilic attack on the ring.

Last Answer : donates electrons that increase electron density at ortho and para positions favoring electrophilic attack.

An organic compound (A) has a molecular weight 78 and an empirical formula CH. (A) is resistant to attack by oxidizing agents but undergoes substitution and addition reactions. X-ray analysis shows that the distance between adjacent carbon atoms is 1.39Å (intermediate between single and double bond lengths). The evidence suggests that compound (A) is (a) Benzene (b) Cyclohexane (c) Toluene (d) n-Hexane

Description : An organic compound (A) has a molecular weight 78 and an empirical formula CH. (A) is resistant to attack by oxidizing agents but undergoes substitution and addition reactions. X-ray analysis shows that the ... suggests that compound (A) is (a) Benzene (b) Cyclohexane (c) Toluene (d) n-Hexane

Last Answer : Benzene

An organic compound (A) has a molecular weight 78 and an empirical formula CH. (A) is resistant to attack by oxidizing agents but undergoes substitution and addition reactions. X-ray analysis shows that the distance between adjacent carbon atoms is 1.39Å (intermediate between single and double bond lengths). The evidence suggests that compound (A) is (a) Benzene (b) Cyclohexane (c) Toluene (d) n-Hexane

Description : An organic compound (A) has a molecular weight 78 and an empirical formula CH. (A) is resistant to attack by oxidizing agents but undergoes substitution and addition reactions. X-ray analysis shows that the ... suggests that compound (A) is (a) Benzene (b) Cyclohexane (c) Toluene (d) n-Hexane

Last Answer : Benzene

Which halogen does not appreciably react with methane in a free-radical substitution reaction? (a) chlorine (b) bromine (c) iodine (d) fluorine

Description : Which halogen does not appreciably react with methane in a free-radical substitution reaction? (a) chlorine (b) bromine (c) iodine (d) fluorine

Last Answer : iodine

How an — OH group attached to carbon in the benzene ring activates benzene towards electrophilic substitution ?

Description : How an — OH group attached to carbon in the benzene ring activates benzene towards electrophilic substitution ?

Last Answer : The lone pair of electrons present on oxygen atom enter into resonance with the benzene ring. As a result, the electron density becomes higher at o- and p- position and due to higher electron density, the ring gets activated towards electrophilic substitution.

Quinoline undergoes nucleophilic substitution on heating with NaNH2 to give (a) 2-Aminoquinoline (b) 4-Aminoquinoline (c) 3-Aminoquinoline (d) 8-Aminoquinoline

Description : Quinoline undergoes nucleophilic substitution on heating with NaNH2 to give (a) 2-Aminoquinoline (b) 4-Aminoquinoline (c) 3-Aminoquinoline (d) 8-Aminoquinoline

Last Answer : 2-Aminoquinoline

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Last Answer : 3-Pyridinesulfonic acid

Aryl halides are less reactive towards nucleophilic substitution as compared to alkyl halides due to (a) Inductive effect (b) Resonance stabilization (c) Tautomerism (d) Stereoisomerism

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Last Answer : Resonance stabilization

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Last Answer : chloride is a better leaving group than methoxide

Which alkyl halides react most readily by nucleophilic substitution? (a) CH3CH2Cl (b) CH3CH2I (c) CH3CH2Br (d) CH3CH2F

Description : Which alkyl halides react most readily by nucleophilic substitution? (a) CH3CH2Cl (b) CH3CH2I (c) CH3CH2Br (d) CH3CH2F

Last Answer : CH3CH2I

Ethylene is obtained from ethyl bromide by : (a) Simple heating (b) Hydrolysis (c) Dehydrohalogenation (d) Nucleophilic substitution

Description : Ethylene is obtained from ethyl bromide by : (a) Simple heating (b) Hydrolysis (c) Dehydrohalogenation (d) Nucleophilic substitution

Last Answer : Dehydrohalogenation

The nucleophilic attack on the esterified carboxyl group of the peptidyl-tRNA occupying the P site and the α-amino group of the new amino acyl tRNA, the number of ATP required by the amino acid on the charged tRNA is (A) Zero (B) One (C) Two (D) Four

Description : The nucleophilic attack on the esterified carboxyl group of the peptidyl-tRNA occupying the P site and the α-amino group of the new amino acyl tRNA, the number of ATP required by the amino acid on the charged tRNA is (A) Zero (B) One (C) Two (D) Four

Last Answer : Answer : A

The α-amino group of the new amino acyl tRNA in the A site carries out a nucleophilic attack on the esterified carboxyl group of the peptidyl tRNA occupying the P site. This reaction is catalysed by (A) DNA polymerase (B) RNA polymerase (C) Peptidyl transferase (D) DNA ligase

Description : The α-amino group of the new amino acyl tRNA in the A site carries out a nucleophilic attack on the esterified carboxyl group of the peptidyl tRNA occupying the P site. This reaction is catalysed by (A) DNA polymerase (B) RNA polymerase (C) Peptidyl transferase (D) DNA ligase

Last Answer : Answer : C

The enzyme amino acyl tRNA synthetase is involved in (A) Dissociation of discharged tRNA from 80S ribosome (B) Charging of tRNA with specific amino acids (C) Termination of protein synthesis (D) Nucleophilic attack on esterified carboxyl group of peptidyl tRNA

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Last Answer : Answer : B

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Description : Give reason: Alkanes undergo only substitution reactions but alkenes and alkynes undergo both substitution and addition reactions.

Last Answer : Alkenes and alkynes have double and triple bonds, which on breaking can add hydrogen atoms to satisfy the valency.

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Description : Ketones react with Grignard reagents to form an addition product which on hydrolysis gives a (a) Primary alcohol (b) Tertiary alcohol (c) Secondary alcohol (d) Ketal

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Description : Which of the following is a free radical substitution reaction?

Last Answer : Which of the following is a free radical substitution reaction? A. `CH_(3)CHO+HCNrarrCH_(3)CH(OH)CN` B. C. D.

Arrange the following compound in reactivity towards EAS (Electrophilic aromatic substitution) reaction ?

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