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Question 1

What type of anions are solvated more strongly in polar protic solvents?

Answer 1

A: Smaller, more electronegative anions.

Question 2

How does strong solvation affect nucleophilicity?

Answer 2

A: It shields the anion, making it less reactive.

Question 3

In polar protic solvents, how does nucleophilicity change down a column of the periodic table?

Answer 3

A: Nucleophilicity increases as the size of the anion increases.

Question 4

What is the relationship between nucleophilicity and basicity in polar protic solvents?

Answer 4

A: They are opposite; smaller anions are better bases but poorer nucleophiles.

Question 5

Which halide ion is the strongest nucleophile in polar protic solvents?

Answer 5

A: I⁻ (iodide ion).

Question 6

Why is I⁻ a better nucleophile than F⁻ in polar protic solvents?

Answer 6

A: I⁻ is less strongly solvated due to its larger size, making it more reactive.

Question 7

Which halide ion is the weakest nucleophile in polar protic solvents?

Answer 7

A: F⁻ (fluoride ion).

Question 8

What is the primary role of polar protic solvents in substitution reactions?

Answer 8

A: To solvate and stabilize ions, influencing nucleophilicity.

Question 9

How does the size of an anion affect its solvation?

Answer 9

A: Larger anions are less strongly solvated, making them better nucleophiles.

Question 10

What is the trend in nucleophilicity for halides (F⁻, Cl⁻, Br⁻, I⁻) in polar protic solvents?

Answer 10

A: I⁻ > Br⁻ > Cl⁻ > F⁻.

Question 11

What does strong solvation of F⁻ in water result in?

Answer 11

A: Reduced nucleophilicity due to shielding by water molecules.

Question 12

In polar protic solvents, why does basicity not directly correlate with nucleophilicity?

Answer 12

A: Solvent interactions reduce the reactivity of smaller, stronger bases.

Question 13

What effect does the electronegativity of an anion have in polar protic solvents?

Answer 13

A: Higher electronegativity leads to stronger solvation, reducing nucleophilicity.

Question 14

Which property of solvents makes them “polar protic”?

Answer 14

A: The ability to form hydrogen bonds.

Question 15

How does methanol (CH₃OH) compare to water (H₂O) in solvating anions?

Answer 15

A: Methanol solvates less strongly than water due to fewer hydrogen bonding interactions.

Question 16

What are polar aprotic solvents incapable of?

Answer 16

A: Hydrogen bonding.

Question 17

What type of interactions do polar aprotic solvents exhibit?

Answer 17

A: Dipole-dipole interactions.

Question 18

Name a common polar aprotic solvent with the formula CH₃COCH₃.

Answer 18

A: Acetone.

Question 19

What is the common abbreviation for tetrahydrofuran?

Answer 19

A: THF.

Question 20

Which polar aprotic solvent is represented by the structure HCON(CH₃)₂?

Answer 20

A: Dimethylformamide (DMF).

Question 21

Why are polar aprotic solvents commonly used in substitution reactions?

Answer 21

A: They do not solvate nucleophiles strongly, allowing them to remain reactive.

Question 22

What differentiates polar aprotic solvents from polar protic solvents?

Answer 22

A: Polar aprotic solvents lack O-H or N-H bonds and cannot form hydrogen bonds.

Question 23

Which solvent among the following is polar aprotic: water, acetone, ethanol?

Answer 23

A: Acetone.

Question 24

How do polar aprotic solvents interact with cations?

Answer 24

A: They stabilize cations through dipole-dipole interactions.

Question 25

What is a key characteristic of all polar aprotic solvents?

Answer 25

A: They have a significant dipole moment but lack hydrogen bond donors.

Question 26

Name two common applications of polar aprotic solvents.

Answer 26

A: Used in nucleophilic substitution reactions (e.g., SN2) and organometallic reactions.

Question 27

What is a nucleophile?

Answer 27

A: A species that donates an electron pair to form a new covalent bond.

Question 28

Give two examples of negatively charged oxygen nucleophiles.

Answer 28

A: −OH (hydroxide) and −OR (alkoxide).

Question 29

Provide an example of a neutral oxygen nucleophile.

Answer 29

A: H2O (water) or ROH (alcohol).

Question 30

What is a common nitrogen-based negatively charged nucleophile?

Answer 30

A: N3−(azide).

Question 31

Name a neutral nitrogen nucleophile.

Answer 31

A: NH3 (ammonia) or RNH2(amine).

Question 32

Identify two examples of carbon-based negatively charged nucleophiles.

Answer 32

A: −CN (cyanide) and −C≡CH (acetylide).

Question 33

What halogens act as negatively charged nucleophiles?

Answer 33

A: C l − Cl − , B r − Br − , and I − I − .

Question 34

Which sulfur species acts as a negatively charged nucleophile?

Answer 34

A: − H S −HS (hydrosulfide) and − R S −RS (thiolate).

Question 35

Name a neutral sulfur nucleophile.

Answer 35

A: H 2 S H 2 ​ S (hydrogen sulfide) or R S H RSH (thiol).

Question 36

What type of nucleophiles are C H 3 C O O − CH 3 ​ COO − (acetate)?

Answer 36

A: Negatively charged oxygen nucleophiles.

Question 37

Which halide ion is the best nucleophile in polar protic solvents?

Answer 37

A: I − I − (iodide).

Question 38

What distinguishes a neutral nucleophile from a negatively charged one?

Answer 38

A: Neutral nucleophiles do not carry a formal negative charge.

Question 39

Why are sulfur-based nucleophiles often stronger than oxygen-based nucleophiles?

Answer 39

A: Sulfur is less electronegative and more polarizable than oxygen, making it more nucleophilic.

Question 40

Which negatively charged nucleophile is commonly used in organic synthesis to introduce a carbon-nitrogen triple bond?

Answer 40

A: − C N −CN (cyanide).

Question 41

How do halogen nucleophiles like C l − Cl − , B r − Br − , and I − I − behave in substitution reactions?

Answer 41

A: They act as good nucleophiles and displace leaving groups in nucleophilic substitution reactions.