Question 1

Which of the following carbocations is the least stable?

Accepted Answer

A methyl carbocation $$\mathrm{CH_3$^+}$$

Question 2

What is the formal charge on the nitrogen atom in the ammonium ion $$\mathrm{NH_4$^+}$$?

Accepted Answer

+1

Question 3

Which of the following compounds is the strongest acid?

Accepted Answer

Trifluoroacetic acid $$\mathrm{CF_3COOH}$$

Question 4

Arrange the following conformations of butane in order of decreasing stability: anti, gauche, eclipsed, fully eclipsed.

Accepted Answer

Anti \u003e Gauche \u003e Eclipsed \u003e Fully Eclipsed

Question 5

Which anion is the strongest base?

Accepted Answer

Methoxide ion $$\mathrm{CH_3O^-}$$

Question 6

Which intermediate is formed during the Fisher esterification of acetic acid and ethanol?

Accepted Answer

A tetrahedral intermediate with both an ethoxy and hydroxy group attached to the central carbon

Question 7

Which of the following is the intermediate in the reduction of acetone with sodium hydride?

Accepted Answer

An enolate ion $$\mathrm{CH_3COCH_2^-}$$

Question 8

Which alkene will produce carbonyl compounds upon ozonolysis followed by reductive work-up?

Accepted Answer

1-butene $$\mathrm{CH_2$=CHCH_2CH_3}$$

Question 9

Which statement about multistep reactions is incorrect?

Accepted Answer

The overall reaction rate is determined by the rate of the fastest step.

Question 10

Why is trifluoroacetic acid $$\mathrm{CF_3COOH}$$ stronger than acetic acid $$\mathrm{CH_3COOH}$$?

Accepted Answer

Because the conjugate base is more stabilized by the electron-withdrawing effect of fluorine atoms.

Question 11

Which of the following is the product of the acid-catalyzed dehydration of 2-butanol?

Accepted Answer

2-butene $$\mathrm{CH_3CH=$$CHCH_3$$}$$

Question 12

Which of the following is the most stable carbanion?

Accepted Answer

Benzyl carbanion $$\mathrm{C_6H_5CH_2^-}$$

Question 13

Which of the following is the intermediate in the trans-hydrogenation of 3-hexyne with $$\mathrm{Na/NH_3$(liquid)}$$?

Accepted Answer

A trans-alkene radical anion

Question 14

Bromination of alkenes is a stereoselective process because:

Accepted Answer

Nucleophilic attack occurs only from the side opposite to the bromine atom in the bromonium ion.

Question 15

Which of the following is the product of the Fisher esterification reaction between acetic acid and ethanol?

Accepted Answer

Ethyl acetate $$\mathrm{CH_3COOCH_2CH_3}$$

Question 16

Which hybridization corresponds to the cationic, radical, and anionic carbon atoms, respectively?

Accepted Answer

$$sp^2$$, $$sp^2$$, $$sp^3$$

Question 17

Conjugation decreases the wavelengths of functional groups such as $$\mathrm{C=O} or$$ $$\mathrm{C=C}$$ because:

Accepted Answer

Bond orders decrease, lowering the energy gap and shifting absorption to shorter wavelengths.

Question 18

What is the number of theoretically possible products in light-initiated bromination of n-butylbenzene $$\mathrm{C_6H_5CH_2CH_2CH_2CH_3}$$, including all positional isomers and stereoisomers (R/S) whenever applicable?

Accepted Answer

8

Question 19

Which of the following is the product of the reaction sequence: $$\mathrm{1. O_3$; 2. H_2O_2/NaOH} on 1-$$hexene?

Accepted Answer

Hexanoic acid $$\mathrm{CH_3$(CH_2$)_4COOH}$$ and formic acid $$\mathrm{HCOOH}$$

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