Kaplan Natural Science Workshop A - wrong answer??

[ScratchMan]

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Please look into the attached OChem questions ( #85) that came from Kaplan Natural Science Workshop A. I cannot agree with Kaplan's answers..


#85: Kaplan answer is C. But, the longest carbon chain is 8 so it should be -octane. I can say it is 2,3,7-trimethyloctane so my answer is E.

please verify if I am right or not.....

thanks.

 

[FROGGBUSTER]

Count the carbons from left to right, it's a nonane chain. No biggy, I think you just missed it. 🙂

 

[herkulease]

Its 9. start from the left methyl either one and just count from left to right don't go towards the branch.

Looking at the name you came up of 2,3,7-trimethyloctane

the only way I can come up with that is that you completely ignore 4 carbons. there are 15 total carbons but your name only says there are 11.

based on the actual longest chain you just ignored carbons 6-9.

 

[nimman1126]

Also for the other attachment (Problem 84). Is the answer B? And shouldnt the oxygen be double bonded to carbons on each side?

 

[dantemac]

The oxygen should be +1, the C is fine (4 bonds like normal).

The chain length is nine, not 8.

 

[ScratchMan]

Thanks all of you guys!! Damn, another miscounting... i should first prep for no more mistake prior to keep studying...