Question 1

Which of the following statements best explains why resonance stabilization affects the acidity (pKa) of a compound?

Accepted Answer

Resonance stabilization delocalizes the negative charge on the conjugate base, making the acid stronger and lowering its pKa.

Question 2

Consider the following acid-base reaction: $$ \mathrm{CH_3COOH} + \mathrm{OH^-} \rightarrow \mathrm{CH_3COO^-} + \mathrm{H_2O} . $$Which statement about the equilibrium position is correct?

Accepted Answer

The equilibrium favors the products because $$ \mathrm{OH^-}  is a $$stronger base than $$ \mathrm{CH_3COO^-} .$$

Question 3

Which of the following is the correct representation of a two-electron arrow in a reaction mechanism?

Accepted Answer

A curved arrow with two barbs ($$ \curvearrowright )$$

Question 4

A student proposes the following mechanism for the acid-catalyzed hydration of an alkene. Which guideline is violated if the student omits the regeneration of the acid catalyst in the final step?

Accepted Answer

All catalysts must be regenerated.

Question 5

Which of the following factors most strongly influences the rate of an $$ \mathrm{S_N1} $$ reaction?

Accepted Answer

The stability of the carbocation intermediate.

Question 6

In the context of organic reaction mechanisms, what is the significance of using 'fishhook' arrows?

Accepted Answer

They represent the movement of a single electron, often in radical reactions.

Question 7

Which of the following compounds would have the lowest pKa value?

Accepted Answer

Acetic acid ($$ \mathrm{CH_3COOH} )$$

Question 8

A reaction mechanism is proposed for the nucleophilic substitution of tert-butyl chloride with water. Which of the following best describes the rate-determining step?

Accepted Answer

Loss of chloride ion to form the carbocation.

Question 9

Which of the following is a correct application of the concept of resonance in predicting the major product of the nitration of benzene?

Accepted Answer

The nitro group will add to the position with the highest electron density due to resonance stabilization.

Question 10

Which of the following statements about equilibrium in organic reactions is correct?

Accepted Answer

Equilibrium is achieved when the rates of the forward and reverse reactions are equal.

Question 11

In the acid-catalyzed hydration of ethene, which intermediate is formed after the initial protonation step?

Accepted Answer

A carbocation intermediate ($$ \mathrm{CH_3CH_2^+} )$$

Question 12

Which of the following is the best reason why tertiary alkyl halides undergo $$ \mathrm{S_N1} $$ reactions more readily than primary alkyl halides?

Accepted Answer

Tertiary carbocations are more stabilized by hyperconjugation and inductive effects.

Question 13

Which of the following is a correct statement about the use of curved arrows in organic mechanisms?

Accepted Answer

Curved arrows represent the movement of electrons during bond formation and breaking.

Question 14

A student is asked to draw the mechanism for the base-catalyzed hydrolysis of an ester. Which of the following steps must be included to ensure the mechanism is mass and charge balanced?

Accepted Answer

Show the formation of the tetrahedral intermediate and the regeneration of the base catalyst.

Question 15

Which of the following best describes the effect of electron-withdrawing groups on the acidity of carboxylic acids?

Accepted Answer

They increase acidity by stabilizing the conjugate base through delocalization of negative charge.

Question 16

Which of the following is the correct order of increasing nucleophilicity in aqueous solution?

Accepted Answer

$$ \mathrm{H_2O} \u003c \mathrm{Cl^-} \u003c \mathrm{OH^-} $$

Question 17

Which of the following is a correct statement about the role of solvents in $$ \mathrm{S_N2} $$ reactions?

Accepted Answer

Polar aprotic solvents increase the rate of $$ \mathrm{S_N2} $$ reactions by stabilizing the nucleophile.

Question 18

Which of the following is the correct representation of equilibrium in a chemical equation?

Accepted Answer

$$ \rightleftharpoons $$

Question 19

A student is asked to distinguish between irreversible and reversible steps in a reaction mechanism. Which symbol should be used for an irreversible step?

Accepted Answer

$$ \rightarrow $$

Organic Chemistry I: Course Syllabus, Structure, and Mechanism Guidelines

Guida di studio - Domande di pratica

Study guide - Flashcard