Question 1

Why do alcohols in their neutral form not undergo substitution reactions with halide nucleophiles, as shown in the first image?

Accepted Answer

Because the hydroxyl group (OH) is a strongly basic leaving group and does not leave easily.

Question 2

What is the role of acid in the substitution reaction of alcohols, as depicted in the second image?

Accepted Answer

It protonates the OH group, converting it into a better leaving group (water).

Question 3

Which mechanism is most likely for the substitution of a tertiary alcohol with HBr, as shown in the third image?

Accepted Answer

SN1 mechanism, involving carbocation formation.

Question 4

In the substitution of ethanol (a primary alcohol) with HBr, what is the most likely mechanism, as shown in the fourth image?

Accepted Answer

SN2 mechanism, with backside attack by the nucleophile.

Question 5

What is the final product when 1-butanol is oxidized with $$ \mathrm{H_2CrO_4}  as $$shown in the fifth image?

Accepted Answer

Butanoic acid ($$ \mathrm{CH_3CH_2CH_2COOH} )$$

Question 6

What is the product of oxidizing 2-butanol with $$ \mathrm{H_2CrO_4} $$, as shown in the sixth image?

Accepted Answer

Butanone ($$ \mathrm{CH_3CH_2COCH_3} )$$

Question 7

Why do ethers only undergo substitution reactions under acidic conditions, as shown in the seventh image?

Accepted Answer

Because the RO− group is a poor leaving group and must be protonated to become a good leaving group.

Question 8

In the acid-catalyzed cleavage of a tertiary ether, as shown in the eighth image, what is the key intermediate?

Accepted Answer

A carbocation formed after water departs.

Question 9

During the acid-catalyzed cleavage of a primary ether, as shown in the ninth image, where does the nucleophile attack?

Accepted Answer

At the less sterically hindered carbon via an SN2 mechanism.

Question 10

What is the IUPAC name for the compound shown in the tenth image (a three-membered cyclic ether)?

Accepted Answer

Ethylene oxide

Question 11

What is the correct IUPAC name for the compound shown in the eleventh image?

Accepted Answer

1,2-epoxy-2-methylpropane

Question 12

In the acid-catalyzed ring opening of ethylene oxide with HBr, as shown in the twelfth image, what is the major product?

Accepted Answer

$$ \mathrm{HOCH_2CH_2Br} $$

Question 13

When an unsymmetrical epoxide reacts with methanol under acidic conditions, as shown in the thirteenth and fourteenth images, which carbon does the nucleophile attack and why?

Accepted Answer

The more substituted carbon, due to partial carbocation character.

Question 14

What is the major product when an epoxide reacts with a strong nucleophile under basic conditions, as shown in the fifteenth image?

Accepted Answer

Nucleophilic attack at the less substituted carbon, giving an alcohol.

Question 15

What is a real-world health risk associated with the formation of epoxides from aromatic hydrocarbons during grilling, as shown in the sixteenth image?

Accepted Answer

Formation of carcinogenic polyaromatic hydrocarbons (PAHs) that can react with DNA.

Question 16

Which DNA base is most susceptible to alkylation by epoxides, as discussed in the study materials?

Accepted Answer

Guanine, especially at the N7 position.

Question 17

Why is toluene considered a safer alternative to benzene as a solvent, based on the metabolic oxidation pathways described?

Accepted Answer

Because toluene is oxidized at the benzylic carbon, avoiding the formation of carcinogenic epoxides.

Question 18

What is the mechanism of the reaction between ethyl bromide and methylamine, as shown in the last image?

Accepted Answer

SN2 mechanism, with direct nucleophilic substitution.

Question 19

Why do amines not undergo substitution or elimination reactions even when protonated, as described in the study materials?

Accepted Answer

Because the leaving group (ammonium ion) is too basic and does not leave easily.

Alcohols, Amines, Ethers, Epoxides, and Thiols: Reactions and Properties

Guida di studio - Domande di pratica

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