Question #77223

Dec 8, 2016

A. 3 mono octanene
B. is impossible as one C at the bottom appears to have 5 bonds and can only have 4

Explanation:

A. There are eight carbons so octane but there is a double bond so octene. The bond is on the third carbon so 3 there is only one double bond so mono. The mono can be deleted as it is clear that there is only one bond as there is only one number listed.

B. If the carbon with 5 bonds had only 4 bonds the molecule would have nine carbons in a line and one carbon in a side chain

This would then be nonene. The double bond is on the fourth carbon (count from the shortest direction four from the top counting down and five counting from the right. The one carbon side chain is on the third carbon. so

3 methyl 4 noene

Dec 17, 2016

The names are A) 5-methylhept-3-yne and B) 3-ethyl-5-methylhept-2-ene.

A)

${\text{CH"_3"CH"_2"C≡CCHCH}}_{3}$
$\textcolor{w h i t e}{m m m m m m m} |$
$\textcolor{w h i t e}{m m m m m m l l} {\text{CH}}_{2}$
$\textcolor{w h i t e}{m m m m m m m} |$
$\textcolor{w h i t e}{m m m m m m l l} {\text{CH}}_{3}$

You pick the longest continuous chain and number it from the end closest to the triple bond.

That gives you the base name hept-3-yne.

There is a methyl substituent at $\text{C5}$, so the complete name is 5-methylhept-3-yne.

B)

$\textcolor{w h i t e}{m m m m m l l} {\text{CH}}_{3}$
$\textcolor{w h i t e}{m m m m m m} |$
$\textcolor{w h i t e}{m m m m m l l} {\text{CH}}_{2}$
$\textcolor{w h i t e}{m m m m m m} |$
$\textcolor{w h i t e}{m} {\text{CH"_3"CH=CCH"_2"CHCH"_2"CH}}_{3}$
$\textcolor{w h i t e}{m m m m m m m m m} |$
$\textcolor{w h i t e}{m m m m m m m m l l} {\text{CH}}_{3}$

You pick the longest continuous chain and number it from the end closest to the double bond.

That gives you the base name hept-2-ene.

There is an ethyl substituent at $\text{C3}$ and a methyl substituent at $\text{C5}$.

You list the substituents in alphabetical order, so the complete name
is 3-ethyl-5-methylhept-2-ene.