Organic Chemistry ExamKrackers Lecture question.

[UIC]

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PG. 18 Problem # 16

Natural gas consists of chiefly methane, but also contains ethane, propane, butane and isobutene. Which of the following compounds is NOT found in natural gas?

A. sec-butane
B. 2-methylbutane
c. olefin (CH2CH2)
d. cyclopropane.

I chose C but the correct answer is B. Can someone explain why?

 

[rinsterman12]

I believe the answer lies in the structure of isobutene. If you look at the structure of isobutene is does indeed include olefin, the carbon carbon double bond, so c is wrong. B is the correct answer because do you see 2-methylbutane in any of those molecules? No...Hope this helps.

 

[fizzgig]

i assume the point they were making is that only up to 4carbons will be found. i think the rule is starting with 5carbons a hydrocarbon will be a liquid at room temp.

2methyl butane is butane with an EXTRA methyl sitting on it. it has 5 carbons.

 

[MizuNoHane]

i assume the point they were making is that only up to 4carbons will be found. i think the rule is starting with 5carbons a hydrocarbon will be a liquid at room temp.

2methyl butane is butane with an EXTRA methyl sitting on it. it has 5 carbons.

That's the way I looked at it too, and it's the justification EK gives for the answer.