Question 1

Which of the following best describes a hydrohalogenation reaction of an alkene?

Accepted Answer

A reaction where hydrogen and a halogen (such as Cl or Br) are added to a carbon-carbon double bond.

Question 2

According to Markovnikov's Rule, in the addition of HBr to 2-methyl-2-butene, where will the Br atom attach?

Accepted Answer

To the carbon with fewer hydrogen atoms.

Question 3

What is the major product when 1-butene reacts with HCl?

Accepted Answer

2-chlorobutane

Question 4

Which of the following best explains why Markovnikov's Rule applies to hydrohalogenation reactions?

Accepted Answer

The carbocation intermediate is more stable when formed on the carbon with fewer hydrogens (more substituted).

Question 5

What is the product of the hydrohalogenation of cyclohexene with HBr?

Accepted Answer

Bromocyclohexane

Question 6

A student reacts 2-methyl-2-butene with excess HCl. What is the name of the major organic product?

Accepted Answer

2-chloro-2-methylbutane

Question 7

Which of the following is the correct balanced equation for the hydrohalogenation of 1-pentyne with excess HBr?

Accepted Answer

$\mathrm{CH_3CH_2C \equiv CH} + 2\ \mathrm{HBr} \rightarrow \mathrm{CH_3CH_2CBr_2CH_3}$

Question 8

In the hydrohalogenation of an alkyne with excess HCl, what is the expected product?

Accepted Answer

A dihalide with both halogens on the same carbon.

Question 9

A patient accidentally ingests a compound that reacts with HBr in the stomach. If the compound is 1-hexene, what is the major product formed?

Accepted Answer

2-bromohexane

Question 10

Which of the following statements about hydrohalogenation of alkynes is correct?

Accepted Answer

With excess HX, both halogens add to the same carbon, forming a geminal dihalide.

Question 11

Given the following reaction: $\mathrm{CH_3CH=CH_2} + \mathrm{HCl} \rightarrow$ ? What is the major product?

Accepted Answer

2-chloropropane

Question 12

Which of the following best describes the regioselectivity observed in hydrohalogenation reactions of unsymmetrical alkenes?

Accepted Answer

The hydrogen adds to the carbon with more hydrogens, and the halogen adds to the carbon with fewer hydrogens.

Question 13

A chemist adds HCl to 3,3-dimethyl-1-butyne in excess. What is the IUPAC name of the major product?

Accepted Answer

3,3-dimethyl-2,2-dichlorobutane

Question 14

Which of the following is a correct statement about the mechanism of hydrohalogenation of alkenes?

Accepted Answer

The reaction proceeds via a carbocation intermediate.

Question 15

If 1-methylcyclohexene reacts with HBr, what is the major product?

Accepted Answer

1-bromo-1-methylcyclohexane

Question 16

A student is asked to predict the product of the reaction between 2-butyne and excess HCl. Which of the following is correct?

Accepted Answer

2,2-dichlorobutane

Question 17

Which of the following best explains why hydrohalogenation of alkynes with excess HX leads to a geminal dihalide?

Accepted Answer

The first halogen addition makes the second addition to the same carbon more favorable.

Question 18

Which of the following is the correct product for the hydrohalogenation of 3-methyl-1-butene with HBr?

Accepted Answer

2-bromo-3-methylbutane

Question 19

A hydrohalogenation reaction is performed on 1-hexyne with excess HCl. What is the major product?

Accepted Answer

1,1-dichlorohexane

Question 20

Which of the following best describes the difference between hydrohalogenation of alkenes and alkynes?

Accepted Answer

Alkynes can react with two equivalents of HX to form geminal dihalides, while alkenes react with one equivalent to form alkyl halides.

Hydrohalogenation Reactions in Organic Chemistry

Study Guide - Practice Questions