Q: Which of the following IR absorptions would indicate the presence of an O-H group?

$$\sim 3300\ \text{cm}^{-1} ($$broad)

Question 1

Which of the following functional groups is most likely responsible for a strong IR absorption near $$1700\ 	ext{cm}^{-1} in $$the IR spectrum?

Accepted Answer

Ketone

Question 2

A compound with the molecular formula $$\mathrm{C$$_{10}$$H_{12}O_2$}$$ shows a $$^1\mathrm{H}$$ NMR septet at $$2.9$$ ppm integrating to $$1H $$and a doublet at $$1.2$$ ppm integrating to $$6H. $$What is the most likely structural fragment present?

Accepted Answer

Isopropyl group

Question 3

Which of the following statements about $$^{13}\mathrm{C}$$ NMR is correct?

Accepted Answer

The number of signals in $$^{13}\mathrm{C}$$ NMR corresponds to the number of unique carbon environments.

Question 4

Given the following $$^1\mathrm{H}$$ NMR data: a triplet at $$1.0$$ ppm (3H), a quartet at $$2.5$$ ppm (2H), and a singlet at $$9.8$$ ppm (1H), which compound is most likely?

Accepted Answer

Propanal

Question 5

Which of the following best explains why tert-butyl alcohol has a higher boiling point than diethyl ether?

Accepted Answer

tert-Butyl alcohol can form hydrogen bonds, while diethyl ether cannot.

Question 6

In the reaction below, what is the major organic product?

$$\mathrm{(CH_3$)_3CBr + NaOH \rightarrow}$$

Accepted Answer

$$\mathrm{(CH_3$)_3COH}$$

Question 7

Which of the following compounds will have the highest boiling point?

A. $$n-$$pentane
B. 2-methylbutane
C. 2,2-dimethylpropane
D. 1-butanol

Accepted Answer

D. 1-butanol

Question 8

A $$^1\mathrm{H}$$ NMR spectrum shows a singlet at $$2.1$$ ppm integrating to $$3H $$and a quartet at $$2.4$$ ppm integrating to $$2H. $$Which functional group is most likely present?

Accepted Answer

Ketone

Question 9

Which of the following best describes the splitting pattern for the methyl group in ethyl acetate ($$\mathrm{CH_3COOCH_2CH_3}) in$$ $$^1\mathrm{H}$$ NMR?

Accepted Answer

Triplet

Question 10

Which of the following is the best explanation for the downfield shift (higher ppm) of a proton in $$^1\mathrm{H}$$ NMR?

Accepted Answer

The proton is deshielded due to electronegative atoms nearby.

Question 11

Which of the following IR absorptions would indicate the presence of an O-H group?

Accepted Answer

$$\sim 3300\ 	ext{cm}^{-1} ($$broad)

Question 12

Which of the following best describes the product of the reaction: $$\mathrm{CH_3COOH + NaOH \rightarrow}$$

Accepted Answer

$$\mathrm{CH_3COONa + H_2O}$$

Question 13

Which of the following is the correct order of increasing boiling point for the following compounds?

I. $$n-$$pentane
II. 2-methylbutane
III. 2,2-dimethylpropane

Accepted Answer

III \u003c II \u003c I

Question 14

Which of the following statements about hydrogen bonding is correct?

Accepted Answer

Hydrogen bonding increases the boiling point of a compound.

Question 15

A $$^1\mathrm{H}$$ NMR spectrum shows a triplet at $$1.2$$ ppm (3H), a quartet at $$2.4$$ ppm (2H), and a singlet at $$9.8$$ ppm (1H). Which compound is most likely?

Accepted Answer

Propanal

Question 16

Which of the following best explains why $$n-$$pentane has a higher boiling point than 2,2-dimethylpropane?

Accepted Answer

$$n-$$Pentane has more surface area for dispersion forces.

Organic Chemistry: NMR, IR, and Reaction Mechanism Study Guide

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