Question 1

Which of the following best explains why a hydride shift might occur during the addition of HBr to 3-methyl-2-pentene?

Accepted Answer

To stabilize the carbocation by forming a more substituted carbocation.

Question 2

Which of the following correctly describes the geometry and hybridization of the carbon atoms in ethyne (acetylene)?

Accepted Answer

Linear geometry with $$sp$$ hybridization.

Question 3

Which product is formed when 2-butanol is oxidized with potassium dichromate ($$K_2Cr_2O_7) $$under acidic conditions?

Accepted Answer

Butan-2-one

Question 4

Which of the following statements about the Diels-Alder reaction is correct?

Accepted Answer

It is a concerted reaction between a conjugated diene and a dienophile.

Question 5

What is the major product when 1-butyne reacts with excess $$H_2 in $$the presence of a palladium catalyst?

Accepted Answer

Butane

Question 6

Which of the following best explains why phenol ($$C_6H_5OH) is $$more acidic than cyclohexanol?

Accepted Answer

The phenoxide ion is stabilized by resonance delocalization of the negative charge.

Question 7

Which of the following is the correct mechanism for the acid-catalyzed hydration of 1-butene?

Accepted Answer

Protonation of the alkene to form a carbocation, followed by nucleophilic attack by water, then deprotonation.

Question 8

Which of the following statements about the reactivity of epoxides in acidic versus basic conditions is correct?

Accepted Answer

In acidic conditions, nucleophilic attack occurs at the more substituted carbon; in basic conditions, at the less substituted carbon.

Question 9

Which of the following is the correct IUPAC name for the compound $$CH_3CH_2OCH_2CH_3$$?

Accepted Answer

Ethoxyethane

Question 10

Which of the following best describes the effect of electron-withdrawing groups on the pKa of a substituted phenol?

Accepted Answer

They lower the pKa, making the phenol more acidic.

Question 11

Which of the following is the correct mechanism for the formation of a sulfonium ion from a thiol?

Accepted Answer

Reaction of a thiol with an alkyl halide, followed by nucleophilic attack by the sulfur atom.

Question 12

Which of the following is the correct product of the reaction between benzene and bromine ($$Br_2) in $$the presence of $$FeBr_3$$?

Accepted Answer

Bromobenzene

Question 13

Which of the following best explains why tertiary amines are generally more basic than primary amines?

Accepted Answer

Alkyl groups donate electron density to nitrogen, stabilizing the positive charge in the conjugate acid.

Question 14

Which of the following is the correct structure for para-nitrotoluene?

Accepted Answer

A benzene ring with a methyl group and a nitro group on opposite carbons (positions 1 and 4).

Question 15

Which of the following is the correct outcome when ethanol reacts with sodium metal?

Accepted Answer

Formation of sodium ethoxide and hydrogen gas.

Question 16

Which of the following best describes the difference between isolated and conjugated diene addition reactions?

Accepted Answer

Conjugated dienes can undergo 1,2- and 1,4-addition, while isolated dienes react independently at each double bond.

Question 17

Which of the following is the correct mechanism for the formation of a disulfide bond from two thiol molecules?

Accepted Answer

Oxidation of two thiol molecules to form a disulfide ($$R-S-S-R).$$

Question 18

Which of the following is the correct product when 1,3-butadiene reacts with ethene in a Diels-Alder reaction?

Accepted Answer

Cyclohexene

Question 19

Which of the following is the correct order of carbocation stability?

Accepted Answer

Benzyl \u003e Allyl \u003e Tertiary \u003e Secondary \u003e Primary \u003e Methyl

Organic Chemistry: Alkenes, Alkynes, Alcohols, Ethers, Amines, Thiols, and Aromaticity

Guida di studio - Domande di pratica