Question 1

Match the chemical descriptors to the following molecules:
 
-Weak electrophile

Accepted Answer

A is the only molecule with a partial negative charge, making it a weak electrophile. The other molecules do not have any significant electrophilic properties.

Question 2

Match the chemical descriptors to the following molecules:
 
-Strong electrophile

Accepted Answer

Molecule B contains a strong electrophile due to the positively charged nitrogen atom, which makes it a good choice for this descriptor. The other molecules do not contain strong electrophiles.

Question 3

Match the chemical descriptors to the following molecules:
 
-Weak nucleophile

Accepted Answer

C

Question 4

Match the chemical descriptors to the following molecules:
 
-Strong nucleophile

Accepted Answer

The answer of Match the chemical descriptors to the following...

Question 5

From the following anions, pick out the one which is the most stable leaving group.

Accepted Answer

The answer of From the following anions, pick out the...

Question 6

For the following reaction, pick out the major product:

Accepted Answer

The answer of For the following reaction, pick out the...

Question 7

Match the chemical descriptors to the species in the following reaction: -^-SAc

Accepted Answer

In every chemical reaction, there are different species with different roles. A nucleophile is a species that donates an electron pair to another molecule or ion (in this case, it could be the oxygen in water), the leaving group is the species that departs the molecule with the electrons displaced (in this case, it's the methyl group from the TMS group), the electrophile is the species that accepts an electron pair (in this case, it's the carbonyl carbon of the aldehyde), and the counter ion is the ion that balances the charge in the reaction (in this case, it could be a proton from the acid used to catalyze the reaction). Therefore, all the choices are the best options for the given descriptors.

Question 8

Match the chemical descriptors to the species in the following reaction: -^-OTs

Accepted Answer

The tosylate ion (OTs-) is a good leaving group because it is a weak base and a good nucleophile.

Question 9

Match the chemical descriptors to the species in the following reaction: -CH₃OTs

Accepted Answer

The answer of Match the chemical descriptors to the species...

Question 10

Match the chemical descriptors to the species in the following reaction: -K⁺

Accepted Answer

K⁺ is a counter ion, often used to balance the charge of anions in a solution. It is not a nucleophile, leaving group, or electrophile.

Question 11

For a S_N2 reaction, pick out the strongest nucleophile from the following species: A: $ \mathrm{PhO} $ B: $ \mathrm{EtOH} $ C:$ \mathrm{MeCO}_{2}^{-} $ D: EtO E: $ \mathrm{H}_{2} \mathrm{O} $

Accepted Answer

EtO (ethoxide ion) is a strong nucleophile due to its negative charge and the presence of an alkoxide group, which makes it more reactive in SN2 reactions compared to the other options.

Question 12

For the following S_N2 reaction, what would be the relative rate of reaction if the concentrations of the alkyl bromide and potassium acetate (CH₃CO₂K) were tripled?

Accepted Answer

The answer of For the following S_N2 reaction, what would...

Question 13

Which of the following factors increase the rate of an S_N1 reaction? Please select all that apply.

Accepted Answer

The answer of Which of the following factors increase the...

Question 14

What product(s) would you expect from the following S_N2 reaction?

Accepted Answer

The answer of What product(s) would you expect from the...

Question 15

From the following bromides, pick out those which can react by a S_N2 mechanism. Please select all that apply.

Accepted Answer

The answer of From the following bromides, pick out those...

Question 16

Which of the following alkyl halides has the fastest rate for a S_N1 reaction?

Accepted Answer

The rate of a S_N1 reaction is determined by the stability of the carbocation intermediate formed. In this case, the carbocation formed will be tertiary, and hence, the more stable the alkyl halide, the faster the formation of the carbocation and the reaction rate. Among the given options, D is the only tertiary alkyl halide, and hence it will have the fastest rate of reaction.

Question 17

From the following benzylic chlorides, pick out the one which is the poorest electrophile for a S_N1 reaction:

Accepted Answer

The answer of From the following benzylic chlorides, pick out...

Question 18

For the following reaction, pick out the major product:

Accepted Answer

The answer of For the following reaction, pick out the...

Question 19

Which of the following alkyl bromides can react with a base in an E2 elimination?

Accepted Answer

The answer of Which of the following alkyl bromides can...

Question 20

What is the major product of the following reaction?

Accepted Answer

The answer of What is the major product of the...

Quiz 20: Halogenoalkanes: Substitution and Elimination Reactions

Match the chemical descriptors to the following molecules: -Weak electrophile

Match the chemical descriptors to the following molecules: -Strong electrophile

Match the chemical descriptors to the following molecules: -Weak nucleophile

Match the chemical descriptors to the following molecules: -Strong nucleophile

From the following anions, pick out the one which is the most stable leaving group.

For the following reaction, pick out the major product:

Match the chemical descriptors to the species in the following reaction: -^-SAc

Match the chemical descriptors to the species in the following reaction: -^-OTs

Match the chemical descriptors to the species in the following reaction: -CH₃OTs

Match the chemical descriptors to the species in the following reaction: -K⁺

For a S_N2 reaction, pick out the strongest nucleophile from the following species: A: $\mathrm{PhO}$ B: $\mathrm{EtOH}$ C: $\mathrm{MeCO}_{2}^{-}$ D: EtO E: $\mathrm{H}_{2} \mathrm{O}$

For the following S_N2 reaction, what would be the relative rate of reaction if the concentrations of the alkyl bromide and potassium acetate (CH₃CO₂K) were tripled?

Which of the following factors increase the rate of an S_N1 reaction? Please select all that apply.

What product(s) would you expect from the following S_N2 reaction?

From the following bromides, pick out those which can react by a S_N2 mechanism. Please select all that apply.

Which of the following alkyl halides has the fastest rate for a S_N1 reaction?

From the following benzylic chlorides, pick out the one which is the poorest electrophile for a S_N1 reaction:

For the following reaction, pick out the major product:

Which of the following alkyl bromides can react with a base in an E2 elimination?

What is the major product of the following reaction?

Quiz 20: Halogenoalkanes: Substitution and Elimination Reactions

Match the chemical descriptors to the following molecules: -Weak electrophile

Match the chemical descriptors to the following molecules: -Strong electrophile

Match the chemical descriptors to the following molecules: -Weak nucleophile

Match the chemical descriptors to the following molecules: -Strong nucleophile

From the following anions, pick out the one which is the most stable leaving group.

For the following reaction, pick out the major product:

Match the chemical descriptors to the species in the following reaction: --SAc

Match the chemical descriptors to the species in the following reaction: --OTs

Match the chemical descriptors to the species in the following reaction: -CH3OTs

Match the chemical descriptors to the species in the following reaction: -K+

For a SN2 reaction, pick out the strongest nucleophile from the following species: A: PhO \mathrm{PhO} PhO B: EtOH \mathrm{EtOH} EtOH C: MeCO2− \mathrm{MeCO}_{2}^{-} MeCO2−​ D: EtO E: H2O \mathrm{H}_{2} \mathrm{O} H2​O

For the following SN2 reaction, what would be the relative rate of reaction if the concentrations of the alkyl bromide and potassium acetate (CH3CO2K) were tripled?

Which of the following factors increase the rate of an SN1 reaction? Please select all that apply.

What product(s) would you expect from the following SN2 reaction?

From the following bromides, pick out those which can react by a SN2 mechanism. Please select all that apply.

Which of the following alkyl halides has the fastest rate for a SN1 reaction?

From the following benzylic chlorides, pick out the one which is the poorest electrophile for a SN1 reaction:

For the following reaction, pick out the major product:

Which of the following alkyl bromides can react with a base in an E2 elimination?

What is the major product of the following reaction?

Match the chemical descriptors to the species in the following reaction: -^-SAc

Match the chemical descriptors to the species in the following reaction: -^-OTs

Match the chemical descriptors to the species in the following reaction: -CH₃OTs

Match the chemical descriptors to the species in the following reaction: -K⁺

For a S_N2 reaction, pick out the strongest nucleophile from the following species: A: $\mathrm{PhO}$ B: $\mathrm{EtOH}$ C: $\mathrm{MeCO}_{2}^{-}$ D: EtO E: $\mathrm{H}_{2} \mathrm{O}$

For the following S_N2 reaction, what would be the relative rate of reaction if the concentrations of the alkyl bromide and potassium acetate (CH₃CO₂K) were tripled?

Which of the following factors increase the rate of an S_N1 reaction? Please select all that apply.

What product(s) would you expect from the following S_N2 reaction?

From the following bromides, pick out those which can react by a S_N2 mechanism. Please select all that apply.

Which of the following alkyl halides has the fastest rate for a S_N1 reaction?

From the following benzylic chlorides, pick out the one which is the poorest electrophile for a S_N1 reaction: