Question 1

Which of the following statements best explains why alkenes cannot freely rotate around the double bond?

Accepted Answer

The presence of a $$\pi-$$bond formed by side-to-side overlap prevents rotation without breaking the bond.

Question 2

Which of the following compounds is an example of an unsaturated hydrocarbon?

Accepted Answer

1-Butene ($$\mathrm{CH_2$=CHCH_2CH_3})$$

Question 3

A molecule of 2-heptene has the following structure: $$\mathrm{CH_3CH=CHCH_2CH_2CH_2CH_3}. $$What is the correct IUPAC name if there is a methyl group on carbon 5 and a cyclopropyl group on carbon 4?

Accepted Answer

4-cyclopropyl-5-methyl-2-heptene

Question 4

Which of the following best describes the hybridization of the carbon atoms involved in the double bond of ethene ($$\mathrm{C_2H_4}$$)?

Accepted Answer

$$sp^2$$ hybridized

Question 5

Which of the following is a correct statement about geometric (cis-trans) isomerism in alkenes?

Accepted Answer

It arises because rotation around the double bond is restricted, leading to different spatial arrangements of substituents.

Question 6

Which of the following is the correct IUPAC name for a molecule with the structure $$\mathrm{CH_3CH_2CH=$$CHCH_3$$}$$?

Accepted Answer

2-pentene

Question 7

A compound has the formula $$\mathrm{C_4H_8}. $$Which of the following is NOT a possible structure for this compound?

Accepted Answer

2-butyne

Question 8

Which of the following statements about the physical properties of alkenes is correct?

Accepted Answer

Cis and trans isomers of alkenes can have different boiling points due to differences in molecular polarity.

Question 9

Which of the following best describes the E/Z (trans/cis) nomenclature for alkenes?

Accepted Answer

E/Z nomenclature is based on the priority of groups attached to the double-bonded carbons, assigned by atomic number.

Question 10

Which of the following is the correct IUPAC name for a molecule with a four-carbon chain, a hydroxyl group on carbon 2, and a nitro group on carbon 3?

Accepted Answer

3-nitrobutan-2-ol

Question 11

Which of the following functional groups has the highest priority when naming a compound according to IUPAC rules?

Accepted Answer

Carboxylic acid ($$-COOH)$$

Question 12

Which of the following is a correct structural formula for (E)-2-pentene?

Accepted Answer

$$\mathrm{CH_3CH=CHCH_2CH_3}$$ with the two largest groups on opposite sides of the double bond

Question 13

A molecule contains both a carboxyl group and an amino group on a seven-carbon chain. The carboxyl group is on carbon 1, and the amino group is on carbon 5. What is the correct IUPAC name?

Accepted Answer

5-aminoheptanoic acid

Question 14

Which of the following best explains why geometric isomers (cis/trans or E/Z) have different physical properties?

Accepted Answer

The spatial arrangement of groups affects molecular polarity and intermolecular forces.

Question 15

Which of the following is the correct IUPAC name for a molecule with a three-carbon chain, a double bond between carbons 1 and 2, and a methyl group on carbon 2?

Accepted Answer

2-methylprop-1-ene

Question 16

Which of the following statements about the naming of alkenes is correct?

Accepted Answer

The chain is numbered from the end closest to the double bond to give the lowest possible number to the double bond.

Question 17

Which of the following is a correct example of a compound that can exhibit geometric (cis/trans) isomerism?

Accepted Answer

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

Question 18

Which of the following best describes the difference between a primary (1°), secondary (2°), and tertiary (3°) alcohol?

Accepted Answer

A primary alcohol has the $$-OH$$ group attached to a carbon bonded to one other carbon; secondary to two; tertiary to three.

Question 19

Which of the following is the correct IUPAC name for a molecule with a five-carbon chain, a double bond between carbons 2 and 3, and a bromo group on carbon 3 (with the double bond in the E configuration)?

Accepted Answer

(E)-3-bromopent-2-ene

Unsaturated Hydrocarbons and Alkenes: Structure, Nomenclature, and Properties

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