Isomers type?

[LoLCareerGoals]

---

Members do not see this ad.

I am either completely clueless or the book is wrong.

What type of isomers (if at all) are these two:

(i) CH3CH2CHCH2CH3
-----------------|
----------------CH2CH3

(ii) CH3CH2CHCH2CH2CH3
------------------|
-----------------CH3

A. Same compound
B. cis-trans isomers
C. constitutional isomers
D. not isomers (different molecular formula)

Book's answer: B
My answer: C

Thoughts?

 

[Charles Darwin]

Where are the double bonds? If there aren't any double bonds, there cannot be cis-/trans- isomerism. I thought they were constitutional isomers considering they have the same number of Cs and Hs but in a different arrangement.

 

[member232]

Constitutional isomers

 

[LoLCareerGoals]

I am using Organic Chemistry (Seventh Edition) by L.G. Wade.
Anyone else has this book? Are answers confirmed incorrect?

 

[member232]

What's your answer and the book answer?

Regardless of the book, I think this is a pretty simple question to not have any tricks and the answer is undoubtedly constitutional isomers.

Can't be same compound-- confirmation: different IUPAC names
Cant be cis/trans for Charles Darwin's reason
Definitely same molecular formula-- same number of C's and H's... lol I counted just to double check

 

[LoLCareerGoals]

See the OP (asnwers whited out to give people a chance to give unbiased answers).
I am just concerned because I am using this book for self study and if it is riddled with wrong answers, I could end up learning things incorrectly when topics become more advanced.

 

[V5RED]

Which page is this on? I have the book and want to check it for myself.

 

[LoLCareerGoals]

problem is on page 59, answer is on A1 (page 1263 I guess).

 

[V5RED]

problem is on page 59, answer is on A1 (page 1263 I guess).

It must be a mistake. In the solution manual it is listed as constitutional isomers.

 

[johnnybravo19]

The answer is C

Step one: name the longest chain
Compound I is Pentane
Compound II is Hexane

At this point, you would know that they are isomers, because they have the same number of carbons, and they're alkanes. Remember CnH2n+2 for alkanes

Step two(if you wanna go the extra mile for tougher questions): add the substituents as a prefix starting with the substituent that would be on the lowest number carbon. Put a dash only between numbers and letters
Compound I is 3-ethylpentane
Compound II is 4-methylhexane

Use simple reasoning skills

xA. Same compound--They're not the same from what I described
xB. cis-trans isomers--There is no pi bonds here
C. constitutional isomers
xD. not isomers (different molecular formula)-- As long as they have they have same number of pi bonds (in this case zero because they're alkane), and they have the same number carbons, you're good (CnH2n+2)

 

[whoknows87]

if 2 compounds have 2 different IUPAC names but same formula that makes them Constitutional isomers correct?

 

[DrSmart21]

C. Constitutional isomers

C.Isomers Compounds that have the same molecular formula but different chemical structures..

 

[LoLCareerGoals]

Guys we've established that the book in wrong in this instance. At this point I am just interested to know how often it is wrong so if any of you have the book and have worked problems in it, I would like to hear your comments on how often book's answers are incorrect.