page 26 and 27

Question 1

Basicity:

Answer 1

Definition: Measures how readily an atom donates its electron pair to a proton (H⁺).
Nature: It is a thermodynamic property.
Characteristic: Determined by an equilibrium constant (Ka) in acid-base reactions.
Focus: Stability of the base and the resulting conjugate acid.

Question 2

Nucleophilicity:

Answer 2

Definition: Measures how readily an atom donates its electron pair to an atom (usually a carbon in a substitution reaction).
Nature: It is a kinetic property.
Characteristic: Determined by a rate constant (k) for reaction speed.
Focus: Speed of bond formation with the electrophile.

Question 3

Key Takeaways

Answer 3

Interrelation:
Both involve electron pair donation but differ in target and measurement criteria.
Basicity focuses on protons, while nucleophilicity focuses on atoms (electrophiles).
Distinction:
Thermodynamics vs. Kinetics:
Basicity is about energy equilibrium and stability.
Nucleophilicity is about reaction speed.

Question 4

What does basicity measure?

Answer 4

Answer: How readily an atom donates its electron pair to a proton.

Question 5

What is the property type of basicity?

Answer 5

Answer: Basicity is a thermodynamic property characterized by an equilibrium constant (Ka).

Question 6

What does nucleophilicity measure?

Answer 6

Answer: How readily an atom donates its electron pair to other atoms (e.g., electrophilic carbons).

Question 7

What is the property type of nucleophilicity?

Answer 7

Answer: Nucleophilicity is a kinetic property characterized by a rate constant (k).

Question 8

How are basicity and nucleophilicity interrelated yet different?

Answer 8

Answer: Both involve electron pair donation, but basicity is thermodynamic (focuses on protons), while nucleophilicity is kinetic (focuses on atoms).

Question 9

How does nucleophilicity compare to basicity for nucleophiles with the same nucleophilic atom?

Answer 9

A: The stronger base is the stronger nucleophile.

Question 10

Which is a stronger nucleophile, HO⁻ or CH₃COO⁻?

Answer 10

A: HO⁻ is a stronger nucleophile because it is a stronger base.

Question 11

How can the nucleophilicity of HO⁻ and CH₃COO⁻ be compared?

Answer 11

A: By comparing the pKa values of their conjugate acids (H₂O = 15.7, CH₃COOH = 4.8).

Question 12

What is the general relationship between a negatively charged nucleophile and its conjugate acid?

Answer 12

A: A negatively charged nucleophile is always stronger than its conjugate acid.

Question 13

How does nucleophilicity change across a row of the periodic table?

Answer 13

A: Nucleophilicity increases from right to left as basicity increases.

Question 14

Rank the following in order of increasing nucleophilicity:CH₃⁻, ⁻NH₂, ⁻OH, F⁻.

Answer 14

A: F⁻ < ⁻OH < ⁻NH₂ < CH₃⁻.

Question 15

Why is CH₃⁻ more nucleophilic than ⁻OH?

Answer 15

A: CH₃⁻ is a stronger base than ⁻OH.

Question 16

Which factor primarily determines nucleophilicity when comparing similar atoms?

Answer 16

A: The strength of the base.

Question 17

What happens to nucleophilicity as basicity increases for second-row elements?

Answer 17

A: Nucleophilicity increases.

Question 18

Why is HO⁻ a stronger nucleophile than CH₃COO⁻?

Answer 18

A: HO⁻ has a higher pKa value for its conjugate acid, making it a stronger base.

Question 19

Between NH₃ and ⁻NH₂, which is the stronger nucleophile?

Answer 19

A: ⁻NH₂, because it is negatively charged and a stronger base.

Question 20

Compare the nucleophilicity of NH₂⁻ and OH⁻.

Answer 20

A: NH₂⁻ is a stronger nucleophile because it is a stronger base.

Question 21

Why does nucleophilicity decrease from CH₃⁻ to F⁻?
A:

Answer 21

Nucleophilicity decreases because basicity decreases from CH₃⁻ to F⁻ across the periodic table.