Question 1

Which of the following statements best describes constitutional (structural) isomers?

Accepted Answer

They have the same molecular formula but differ in connectivity.

Question 2

Given the molecular formula $$\mathrm{C_4H_{10}}$$, which of the following is a correct pair of constitutional isomers?

Accepted Answer

n-butane and iso-butane

Question 3

What is the correct IUPAC name for the following structure: $$\mathrm{CH_3$-CH_2$-CH(CH_3$)-CH_2$-CH_3$}$$?

Accepted Answer

2-methylpentane

Question 4

Which rule should be followed when numbering the parent chain in a branched alkane?

Accepted Answer

Number the chain to give the lowest possible number to the first branch point.

Question 5

Which of the following is the correct name for the compound with the structure $$\mathrm{CH_3$-CH_2$-CH_2$-CH_2$-CH_3$}$$?

Accepted Answer

pentane

Question 6

If two chains of equal length are present in a molecule, how do you determine the principal chain for naming?

Accepted Answer

Choose the chain with the greatest number of branches.

Question 7

What is the correct IUPAC name for the following structure: $$\mathrm{CH_3$-CH(CH_3$)-CH_2$-CH_2$-CH_3$}$$?

Accepted Answer

3-methylpentane

Question 8

Which of the following is a correct example of a cycloalkane?

Accepted Answer

cyclohexane

Question 9

Which of the following is the correct name for a molecule with two methyl groups attached to carbon-2 of pentane?

Accepted Answer

2,2-dimethylpentane

Question 10

Which of the following is the correct parent name for an alkane with 8 carbon atoms?

Accepted Answer

octane

Question 11

Which of the following is a correct example of a branched alkyl group with 4 carbon atoms?

Accepted Answer

sec-butyl

Question 12

What is the boiling point trend between n-butane and iso-butane, and what does this indicate about their structures?

Accepted Answer

iso-butane has a lower boiling point than n-butane, indicating more branching decreases boiling point.

Question 13

Which of the following is the correct way to write the name of an alkane with a methyl group on carbon-3 of hexane?

Accepted Answer

3-methylhexane

Question 14

Which of the following is NOT a correct rule for IUPAC alkane nomenclature?

Accepted Answer

Leave spaces between words in the name.

Question 15

Which of the following is the correct IUPAC name for a molecule with the structure $$\mathrm{CH_3$-CH_2$-CH_2$-CH_2$-CH_2$-CH_3$}$$?

Accepted Answer

hexane

Question 16

Which of the following is the correct classification for a carbon atom bonded to only one other carbon atom?

Accepted Answer

primary carbon ($$1^\circ)$$

Question 17

Which of the following is the correct parent name for an alkane with 10 carbon atoms?

Accepted Answer

decane

Question 18

Which of the following is the correct way to number the parent chain when multiple branches are present?

Accepted Answer

Choose the numbering system that gives the lowest number at the first point of difference.

Question 19

Which of the following is a correct example of a branched alkyl group with 3 carbon atoms?

Accepted Answer

isopropyl

Question 20

Which of the following statements about the stability of alkanes is correct?

Accepted Answer

Stability increases with increased branching.

Alkanes: Structure, Nomenclature, and Isomerism

Study Guide - Practice Questions