Question 1

Which of the following molecules would you expect to have the highest boiling point, based on intermolecular forces and molecular polarity?

A. Methane ($\mathrm{CH_4}$)
B. Ethanol ($\mathrm{CH_3CH_2OH}$)
C. Propane ($\mathrm{C_3H_8}$)
D. Diethyl ether ($\mathrm{CH_3CH_2OCH_2CH_3}$)

Accepted Answer

Ethanol ($\mathrm{CH_3CH_2OH}$)

Question 2

Which of the following bonds would you expect to have the highest IR stretching frequency?

A. $\mathrm{C-H}$
B. $\mathrm{C=O}$
C. $\mathrm{O-H}$
D. $\mathrm{C\equiv C}$

Accepted Answer

$\mathrm{O-H}$

Question 3

A compound shows a strong IR absorption at $1715\ \mathrm{cm}^{-1}$. Which functional group is most likely present?

A. Alcohol
B. Ketone
C. Alkene
D. Amine

Accepted Answer

Ketone

Question 4

Which of the following atoms has the highest electronegativity?

A. Nitrogen
B. Oxygen
C. Fluorine
D. Chlorine

Accepted Answer

Fluorine

Question 5

Which of the following is the correct molecular formula for a compound with 5 carbon atoms, 12 hydrogen atoms, and 1 oxygen atom?

A. $\mathrm{C_5H_{12}O}$
B. $\mathrm{C_5H_{10}O}$
C. $\mathrm{C_5H_{12}O_2}$
D. $\mathrm{C_5H_{10}O_2}$

Accepted Answer

$\mathrm{C_5H_{12}O}$

Question 6

Which of the following statements about resonance structures is TRUE?

A. Resonance structures represent different compounds.
B. Resonance structures differ only in the arrangement of atoms.
C. Resonance structures differ only in the arrangement of electrons.
D. Resonance structures are always equally stable.

Accepted Answer

Resonance structures differ only in the arrangement of electrons.

Question 7

Which of the following species is the strongest acid?

A. $\mathrm{CH_3CH_2OH}$
B. $\mathrm{CH_3COOH}$
C. $\mathrm{NH_3}$
D. $\mathrm{H_2O}$

Accepted Answer

$\mathrm{CH_3COOH}$

Question 8

Which of the following is NOT a valid resonance structure for the acetate ion ($\mathrm{CH_3COO^-}$)?

A. Both oxygens have a single negative charge.
B. The negative charge is delocalized over both oxygens.
C. The double bond is between C and one O, with the other O single bonded and negatively charged.
D. The double bond is between C and the other O, with the first O single bonded and negatively charged.

Accepted Answer

Both oxygens have a single negative charge.

Question 9

Which of the following is the best nucleophile in a polar protic solvent?

A. $\mathrm{F^-}$
B. $\mathrm{Cl^-}$
C. $\mathrm{Br^-}$
D. $\mathrm{I^-}$

Accepted Answer

$\mathrm{I^-}$

Question 10

A molecule has the following IR absorptions: $3300\ \mathrm{cm}^{-1}$ (broad), $2100\ \mathrm{cm}^{-1}$, and $1600\ \mathrm{cm}^{-1}$. Which functional groups are most likely present?

A. Alcohol and alkene
B. Amine and alkyne
C. Alcohol and alkyne
D. Carboxylic acid and alkene

Accepted Answer

Alcohol and alkyne

Question 11

Which of the following statements about mass spectrometry is TRUE?

A. The base peak always corresponds to the molecular ion ($M^+$).
B. The molecular ion peak ($M^+$) is always the most intense peak.
C. The base peak is the most abundant ion in the spectrum.
D. The $M^+$ peak is always present in the spectrum.

Accepted Answer

The base peak is the most abundant ion in the spectrum.

Question 12

Which of the following molecules is most likely to have a dipole moment?

A. $\mathrm{CO_2}$
B. $\mathrm{CCl_4}$
C. $\mathrm{CH_3Cl}$
D. $\mathrm{BF_3}$

Accepted Answer

$\mathrm{CH_3Cl}$

Question 13

Which of the following is the correct order of acidity (most acidic to least acidic)?

A. $\mathrm{H_2O} > \mathrm{CH_3COOH} > \mathrm{NH_3}$
B. $\mathrm{CH_3COOH} > \mathrm{H_2O} > \mathrm{NH_3}$
C. $\mathrm{NH_3} > \mathrm{CH_3COOH} > \mathrm{H_2O}$
D. $\mathrm{CH_3COOH} > \mathrm{NH_3} > \mathrm{H_2O}$

Accepted Answer

$\mathrm{CH_3COOH} > \mathrm{H_2O} > \mathrm{NH_3}$

Question 14

Which of the following is the best description of a Lewis acid?

A. A substance that donates a proton
B. A substance that accepts an electron pair
C. A substance that donates an electron pair
D. A substance that accepts a proton

Accepted Answer

A substance that accepts an electron pair

Question 15

Which of the following molecules is most likely to be soluble in water?

A. Hexane ($\mathrm{C_6H_{14}}$)
B. Benzene ($\mathrm{C_6H_6}$)
C. Ethanol ($\mathrm{CH_3CH_2OH}$)
D. Cyclohexane ($\mathrm{C_6H_{12}}$)

Accepted Answer

Ethanol ($\mathrm{CH_3CH_2OH}$)

Question 16

Which of the following is the correct skeletal structure for 2-butanone?

A. $\mathrm{CH_3CH_2COCH_3}$
B. $\mathrm{CH_3COCH_2CH_3}$
C. $\mathrm{CH_3CH_2CH_2COOH}$
D. $\mathrm{CH_3CH_2CH_2CH_2OH}$

Accepted Answer

$\mathrm{CH_3COCH_2CH_3}$

Question 17

Which of the following is the correct electron configuration for a neutral carbon atom?

A. $1s^2\ 2s^2\ 2p^2$
B. $1s^2\ 2s^2\ 2p^4$
C. $1s^2\ 2s^2\ 2p^6$
D. $1s^2\ 2s^2\ 2p^1$

Accepted Answer

$1s^2\ 2s^2\ 2p^2$

Question 18

Which of the following statements about pKa values is TRUE?

A. A lower pKa value indicates a weaker acid.
B. A higher pKa value indicates a stronger acid.
C. A lower pKa value indicates a stronger acid.
D. pKa values are unrelated to acid strength.

Accepted Answer

A lower pKa value indicates a stronger acid.

Question 19

Which of the following is the correct order of bond strength (strongest to weakest)?

A. Triple > Double > Single
B. Single > Double > Triple
C. Double > Triple > Single
D. Double > Single > Triple

Accepted Answer

Triple > Double > Single

Organic Chemistry Exam Study Guide: Atomic Structure, Molecular Properties, Acidity, and Spectroscopy

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