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Question 1

Role of the Leaving Group:

Answer 1

In nucleophilic substitution reactions (R−X+Nu−), the leaving group departs, taking the electron pair from the
C−X bond.
A good leaving group ensures the reaction proceeds efficiently.

Question 2

Stability of the Leaving Group:

Answer 2

The better the leaving group, the more stable it is after departure.
Stability is influenced by how well the group can accommodate the negative charge.

Question 3

Relation to Base Strength:
Weak bases are better leaving groups.

Answer 3

Example:
H2O is a better leaving group than
OH−because it is a weaker base.

Question 4

Examples of Good Leaving Groups:

Answer 4

Halide ions:
I −>Br −>Cl −>F −
(based on increasing stability as bases weaken).
Neutral molecules:
H2O is better than
HO−.

Question 5

Question: What happens to the leaving group during nucleophilic substitution?

Answer 5

Answer: It departs with the electron pair from the
C−X bond, forming
X −.

Question 6

Why is a weaker base a better leaving group?

Answer 6

Answer: Weaker bases are more stable, making them better at accommodating the negative charge.

Question 7

Which is a better leaving group:
Br− or
Cl−?

Answer 7

Answer:
Br−, because it is a weaker base and more stable.

Question 8

Why is
H2O a better leaving group than
OH−?

Answer 8

Answer:
H2O is a weaker base and more stable after leaving.

Question 9

Question: Rank
F
−
F
−
,
C
l
−
Cl
−
,
B
r
−
Br
−
, and
I
−
I
−
in order of leaving group ability.

Answer 9

Answer:
I
−
>
B
r
−
>
C
l
−
>
F
−
I
−
>Br
−
>Cl −>F −
.

Question 10

Question: Is
N
H
3
NH
3
​
a better leaving group than
O
H
−
OH
−
?

Answer 10

Answer: Yes, because
N
H
3
NH
3
​
is a weaker base than
O
H
−
OH
−
.