Q: Rank the following compounds by the number of unique signals in a spin-decoupled $^{13}$C NMR spectrum (from least to most): benzene, toluene, benzoic acid, anisole, and phenol.

Benzene < Toluene < Anisole < Phenol < Benzoic acid

Q: Which of the following reactions would convert a primary alcohol to a carboxylic acid?

$1)\ \text{Na}_2\text{Cr}_2\text{O}_7,\ \text{H}_2\text{SO}_4$; $2)\ \text{H}_2\text{O}$

Question 1

Which of the following compounds would have the furthest downfield shift for a hydrogen in its $^1$H NMR spectrum? Consider the effect of electron-withdrawing groups on chemical shift.

Accepted Answer

Benzoic acid ($C_6H_5COOH$)

Question 2

Rank the following compounds by the number of unique signals in a spin-decoupled $^{13}$C NMR spectrum (from least to most): benzene, toluene, benzoic acid, anisole, and phenol.

Accepted Answer

Benzene < Toluene < Anisole < Phenol < Benzoic acid

Question 3

Which compound would show the highest energy O-H stretch in its IR spectrum?

Accepted Answer

Benzoic acid

Question 4

A compound with molecular formula $C_3H_8O$ shows a strong IR absorption near $3300\ 	ext{cm}^{-1}$ and a triplet at $\delta = 1.1$ ppm in its $^1$H NMR. Which compound is it?

Accepted Answer

1-Propanol

Question 5

Which of the following compounds would show the fewest number of $^{13}$C NMR signals?

Accepted Answer

Benzene

Question 6

A mass spectrum of an unknown alcohol ($C_4H_{10}O$) shows a base peak at $m/z = 31$. Which structure is most likely?

Accepted Answer

1-Butanol

Question 7

Which compound would show a singlet at $\delta = 9-10$ ppm in its $^1$H NMR spectrum?

Accepted Answer

Benzoic acid

Question 8

A compound with molecular formula $C_3H_6O$ shows a strong IR absorption at $1715\ 	ext{cm}^{-1}$ and a singlet at $\delta = 2.1$ ppm in its $^1$H NMR. What is the compound?

Accepted Answer

Acetone

Question 9

Which of the following reactions would convert a primary alcohol to a carboxylic acid?

Accepted Answer

$1)\ 	ext{Na}_2	ext{Cr}_2	ext{O}_7,\ 	ext{H}_2	ext{SO}_4$; $2)\ 	ext{H}_2	ext{O}$

Question 10

Which compound would show a broad IR absorption around $3300\ 	ext{cm}^{-1}$ that disappears upon addition of $D_2O$?

Accepted Answer

Phenol

Question 11

A $^1$H NMR spectrum shows a doublet at $\delta = 1.2$ ppm (integrates to 6H) and a septet at $\delta = 3.0$ ppm (integrates to 1H). Which compound is this most likely?

Accepted Answer

Isopropyl alcohol

Question 12

Which compound would show a strong IR absorption near $1700\ 	ext{cm}^{-1}$ and a singlet at $\delta = 2.5$ ppm in its $^1$H NMR?

Accepted Answer

Acetophenone

Question 13

Which of the following compounds would show the greatest number of unique $^1$H NMR signals?

Accepted Answer

Benzoic acid

Question 14

A compound with molecular formula $C_4H_{10}O$ shows a triplet at $\delta = 0.9$ ppm and a quartet at $\delta = 3.5$ ppm in its $^1$H NMR. Which compound is it?

Accepted Answer

Ethoxyethane (diethyl ether)

Question 15

Which of the following compounds would show a strong IR absorption at $1700\ 	ext{cm}^{-1}$ and a broad absorption at $2500-3300\ 	ext{cm}^{-1}$?

Accepted Answer

Benzoic acid

Question 16

A compound with molecular formula $C_3H_8O$ shows a singlet at $\delta = 1.2$ ppm and a broad peak at $\delta = 2.5$ ppm in its $^1$H NMR. Which compound is it?

Accepted Answer

tert-Butanol

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