Which hydrocarbon is an unsaturated hydrocarbon? a. 2-methylheptane b. 3-ethylpentane c. 1-hexene d. cyclopentane

The correct answer is option C.

1-hexene is an unsaturated hydrocarbon.

2-methylheptane , 3-ethylpentane and cyclopentane have the suffix -ane, which means they are all alkanes . Alkanes do not have any unsaturation or double bonds.

1-hexene, has the suffix -ene, which means that it is an alkene.   Alkanes do have unsaturation or double bonds. As the name indicates, 1-hexene has one double bond.

CH₂=CHCH₂CH₂CH₂CH₃

is an unsaturated hydrocarbon.

Further Explanation:

Hydrocarbons:

The organic compounds consisting of hydrogen and carbon atoms alone are called hydrocarbons. Such compounds can be aromatic, aliphatic, linear, branched or cyclic. Aromatic hydrocarbons, alkanes, cycloalkanes are different types of hydrocarbons.

Types of hydrocarbons:

(I) Saturated hydrocarbons

These are variety of hydrocarbons that contain only single bonds in them and are the simplest hydrocarbons. Saturated hydrocarbons have the general formula of  in which n indicates the number of carbon atoms present in it. Examples of saturated hydrocarbons are methane, ethane, butane and propane.

(II) Unsaturated hydrocarbons

The type of hydrocarbons that has multiple bonds in them are known as unsaturated hydrocarbons. Multiple bonds can be either double or triple bonds. Alkenes are those unsaturated hydrocarbons consisting of double bonds in them. For example, ethene, propene, and pentene are alkenes. Alkynes refer to unsaturated hydrocarbons with triple bonds in them. Ethyne and propyne are examples of alkynes. Alkenes are represented by general formula,   while alkynes are represented by general formula of .

Alkanes use ‘ane’ as suffix in their naming. Alkenes use ‘ene’ as suffix while ‘yne’ is used in naming of alkynes.

Since 2-methylheptane, 3-ethylpentane and cyclopentane have suffix ‘ane’ in their names and are tered as saturated class of hydrocarbons called alkanes. But 1-hexene has suffix ‘ene’, indicating that it belongs to unsaturated hydrocarbons called alkenes. Therefore 1-hexene is an unsaturated hydrocarbon.

Learn more:

1. What is the empirical formula of the compound?

2. Write the name of the hydrocarbon:

Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Hydrocarbons

Keywords: hydrocarbons, saturated, unsaturated, alkene, alkyne, CnH2n+2, CnH2n, CnH2n-2, double bonds, triple bonds, single bonds, 1-hexene, cyclopentane, 2-methylheptane, 3-ethylpentane.

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