page 47

Question 1

How does the number of R groups on the carbon with the leaving group affect the rate of an
S
N
2
S
N
​
2 reaction?

Answer 1

A: As the number of R groups increases, the rate of the
S
N
2
S
N
​
2 reaction decreases

Question 2

Which substrates react most rapidly in
S
N
2
S
N
​
2 reactions?

Answer 2

A: Methyl halides and primary (
1
∘
1
∘
) alkyl halides.

Question 3

How do secondary (
2
∘
2
∘
) alkyl halides react in
S
N
2
S
N
​
2 reactions?

Answer 3

A: They react more slowly compared to methyl and primary alkyl halides.

Question 4

Why do tertiary (
3
∘
3
∘
) alkyl halides not undergo
S
N
2
S
N
​
2 reactions?

Answer 4

A: Steric hindrance prevents the nucleophile from attacking the carbon atom.

Question 5

What role do bulky R groups play in
S
N
2
S
N
​
2 reactions?

Answer 5

A: Bulky R groups near the reaction site increase steric hindrance, slowing the reaction rate.

Question 6

What is steric hindrance in the context of
S
N
2
S
N
​
2 reactions?

Answer 6

A: Steric hindrance refers to the difficulty a nucleophile faces when trying to access the carbon atom due to bulky groups around it.

Question 7

Arrange the following substrates in order of decreasing
S
N
2
S
N
​
2 reactivity: methyl,
1
∘
1
∘
,
2
∘
2
∘
,
3
∘
3
∘
.

Answer 7

A: Methyl >
1
∘
1
∘
>
2
∘
2
∘
>
3
∘
3
∘
.

Question 8

Why does steric hindrance have a significant effect on
S
N
2
S
N
​
2 reactions?

Answer 8

A:
S
N
2
S
N
​
2 reactions require a backside attack, which is hindered by bulky groups around the reaction site.

Question 9

Can tertiary alkyl halides participate in
S
N
2
S
N
​
2 reactions under any conditions?

Answer 9

A: No,
S
N
2
S
N
​
2 reactions are not feasible for tertiary alkyl halides due to excessive steric hindrance.

Question 10

What is the rate-determining step in an
S
N
2
S
N
​
2 reaction?

Answer 10

A: The simultaneous bond-making and bond-breaking process during the nucleophilic attack.