Question

Based on the molecular formula, determine whether each of the following is an alkane, alkene, or alkyne. (Assume that the hydrocarbons are noncyclical and there is no more than one multiple bond.)

a. C3H6
b. C6H12
c. H8H18
d. C7H12

Answer 1

C₃H₆ is an alkene

C₆H₁₂ is an alkene

C₈H₁₈ is an alkane

C₇H₁₂ is an alkyne

Step-by-step explanation:

To determine which of the compound is alkane, alkene, or alkyne,we shall use the general formula of alkane, alkene, and alkyne. This is illustrated below:

General formula for alkane => CₙH₂ₙ₊₂

General formula for alkene => CₙH₂ₙ

General formula for alkyne => CₙH₂ₙ₋₂

For C₃H₆:

n = 3

Alkane => CₙH₂ₙ₊₂ => C₃H₂₍₃₎₊₂ => C₃H₈

Alkene => CₙH₂ₙ => C₃H₂₍₃₎ => C₃H₆

Alkyne => CₙH₂ₙ₋₂ => C₃H₂₍₃₎₋₂ => C₃H₄

Thus, C₃H₆ is an alkene

For C₆H₁₂:

n = 6

Alkane => CₙH₂ₙ₊₂ => C₆H₂₍₆₎₊₂ =>C₆H₁₄

Alkene => CₙH₂ₙ => C₆H₂₍₆₎ => C₆H₁₂

Alkyne => CₙH₂ₙ₋₂ => C₆H₂₍₆₎₋₂ => C₆H₁₀

Thus, C₆H₁₂ is an alkene

For C₈H₁₈:

n = 8

Alkane => CₙH₂ₙ₊₂ => C₈H₂₍₈₎₊₂ => C₈H₁₈

Alkene => CₙH₂ₙ => C₈H₂₍₈₎ => C₈H₁₆

Alkyne => CₙH₂ₙ₋₂ => C₈H₂₍₈₎₋₂ => C₈H₁₄

Thus, C₈H₁₈ is an alkane.

For C₇H₁₂:

n = 7

Alkane => CₙH₂ₙ₊₂ => C₇H₂₍₇₎₊₂ => C₇H₁₆

Alkene => CₙH₂ₙ => C₇H₂₍₇₎ => C₇H₁₄

Alkyne => CₙH₂ₙ₋₂ => C₇H₂₍₇₎₋₂ => C₇H₁₂

Thus, C₇H₁₂ is an alkyne.

SUMMARY:

C₃H₆ is an alkene

C₆H₁₂ is an alkene

C₈H₁₈ is an alkane

C₇H₁₂ is an alkyne