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hydrocarbons (1 Viewer)

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pLuvia

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What is wrong with the following names? Give the correct one.
a) 2 - propyne
b) 5 - hexene
c) 4 - heptene


this is the question
 

Jumbo Cactuar

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The functional assignments are too high. Naming rules say that unneccessarily high or unneccessary functional assignments are wrong.

a) propyne

HC:::C:CH3

2-propyne = 1-propyne = propyne

simplest name is propyne; so that's the correct answer. I'll let you work out the rest...
 

Dreamerish*~

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kadlil said:
What is wrong with the following names? Give the correct one.
a) 2 - propyne
b) 5 - hexene
c) 4 - heptene


this is the question
a) 2-propyne = 1-propyne = propyne (see Jumbo's post :))

b) 5-hexene. You have to count from the end of the carbon chain that would give the double bond the smallest number.

CH2=CH-CH2-CH2-CH2-CH3

Instead of counting from the right hand side which would make it 5-hexene, we count from the left which makes it 1-hexene. In this case 1-hexene does not equal hexene because there are other places where the double bond can occur.

c) This is the same case as b). :)
 
P

pLuvia

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yeh thanks, i asked my teacher about this and she said that you should always name it from the shortest end, but if i named it from the longest end i wouldn't get it wrong

is this true?
 

Dreamerish*~

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kadlil said:
yeh thanks, i asked my teacher about this and she said that you should always name it from the shortest end, but if i named it from the longest end i wouldn't get it wrong

is this true?
Nuh uh, if you name it from the long end, you will get it wrong.

Why do you think there's something wrong with the names you posted? :p
 
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pLuvia

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argh.. stupid teacher she said you wouldn't get it wrong..
 

Dreamerish*~

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kadlil said:
argh.. stupid teacher she said you wouldn't get it wrong..
Are you serious?

It's actually quite important, very important that you know the correct way of naming hydrocarbons.

Give her a slap for me. ;)
 

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