Question 1

Which of the following best describes the legal moves for curved arrow notation in organic reaction mechanisms?

Accepted Answer

A lone pair can become a bond, a bond can become a lone pair, and a bond can move from one atom to another.

Question 2

In the context of nucleophilic attack, which statement is correct regarding the direction of the curved arrow?

Accepted Answer

The tail of the arrow starts on the nucleophile's electrons and the head ends on the electrophilic atom.

Question 3

Which of the following curved arrow moves would violate the octet rule?

Accepted Answer

Moving a lone pair to form a bond with a carbon that already has four bonds.

Question 4

Which of the following is the correct order of carbocation stability from least to most stable?

Accepted Answer

Methyl \u003c Primary \u003c Secondary \u003c Tertiary

Question 5

What is the main reason tertiary carbocations are more stable than primary carbocations?

Accepted Answer

Tertiary carbocations are stabilized by hyperconjugation from three adjacent alkyl groups.

Question 6

In a 1,2-hydride shift, what happens to the hydride and the carbocation?

Accepted Answer

A hydride (H-) migrates from an adjacent carbon to the carbocation, resulting in a new, more stable carbocation.

Question 7

Which of the following best explains why a methyl group stabilizes a carbocation?

Accepted Answer

The methyl group donates electron density into the empty p orbital of the carbocation via hyperconjugation.

Question 8

Which of the following is NOT a valid pattern of arrow pushing in polar reaction mechanisms?

Accepted Answer

Radical formation

Question 9

In the acid-base reaction shown, what is the role of the hydroxide ion ($$\mathrm{OH^-}$$)?

$$\mathrm{OH^-} + H_2CO_3 \rightarrow H_2O + $$HCO_3$$^-$$

Accepted Answer

It acts as a base, accepting a proton from carbonic acid.

Question 10

Which of the following statements about carbocation rearrangements is correct?

Accepted Answer

Carbocation rearrangements occur to form a more stable carbocation, often via 1,2-hydride or 1,2-alkyl shifts.

Question 11

In the multi-step reaction mechanism shown, which step involves the loss of a leaving group?

Accepted Answer

The step where water ($$H_2O) $$departs from the intermediate, leaving behind a carbocation.

Question 12

Which of the following curved arrow moves is NOT allowed in organic mechanisms?

Accepted Answer

Moving a pi bond to a non-adjacent atom, skipping over atoms in between.

Question 13

Which of the following is a common mistake when drawing curved arrows in organic mechanisms?

Accepted Answer

Drawing an arrow that causes a carbon to have five bonds.

Question 14

Which of the following best describes the geometry of a carbocation center?

Accepted Answer

Trigonal planar with a bond angle of $$120^\circ$$

Question 15

Which of the following statements about resonance structures is correct?

Accepted Answer

The greatest contributing resonance structure is the one in which all atoms have complete octets and the least formal charge.

Question 16

Which of the following is a correct description of a 1,2-alkyl shift?

Accepted Answer

An alkyl group migrates from an adjacent carbon to the carbocation, resulting in a new carbocation at the original alkyl position.

Question 17

Which of the following is a valid reason for a carbocation to undergo rearrangement?

Accepted Answer

To form a more stable carbocation via hyperconjugation or resonance stabilization.

Question 18

In the context of acid-base reactions, which of the following statements is true?

Accepted Answer

The base donates a pair of electrons to accept a proton from the acid.

Arrow Pushing Notation and Carbocation Rearrangements in Organic Reaction Mechanisms

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