Turn on thread page Beta
    • Thread Starter
    Offline

    2
    ReputationRep:
    Structural isomerism and stereoisomerism should be considered when answering this question.

    If a molecule contains two non-identical chiral carbon atoms, four optical isomers exist. How many isomers are there with

    ● molecular formula C7H14O and
    ● a five-membered ring and
    ● a tertiary alcohol group? A)4 B)5 C)9 D)13

    Answer is C)9, WHY?
    • Thread Starter
    Offline

    2
    ReputationRep:
    Please help
    Offline

    9
    ReputationRep:
    This is the first isomer I found. (How many chiral centres are there?)
    Name:  Isomer 1.png
Views: 50
Size:  23.8 KB
    This is the second isomer I found. (How many chiral centres are there?) Ofc, there is one more that I will let you find yourself
    Attached Images
     
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by _JB_)
    This is the first isomer I found. (How many chiral centres are there?)
    Name:  Isomer 1.png
Views: 50
Size:  23.8 KB
    This is the second isomer I found. (How many chiral centres are there?) Ofc, there is one more that I will let you find yourself
    Is it possible for you to display it as structural formula, these images confuses me, thanks
    Offline

    9
    ReputationRep:
    Here you go.
    Name:  Isomer 1.png
Views: 47
Size:  15.4 KB
    Attached Images
     
    Offline

    9
    ReputationRep:
    Name:  Isomer 2.png
Views: 50
Size:  20.1 KB
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by _JB_)
    Name:  Isomer 2.png
Views: 50
Size:  20.1 KB
    Name:  擷取.PNG
Views: 43
Size:  31.7 KB

    This is the third isomer I could find, is this correct?
    Offline

    9
    ReputationRep:
    (Original post by _JB_)
    Here you go.
    Name:  Isomer 1.png
Views: 47
Size:  15.4 KB
    isnt this structure incorrect? the 2nd carbon has 5 bonds.
    Offline

    16
    ReputationRep:
    Name:  IMG_20180411_170850.jpg
Views: 46
Size:  43.9 KB
    Offline

    9
    ReputationRep:
    (Original post by ROadmanKys)
    isnt this structure incorrect? the 2nd carbon has 5 bonds.
    Just accident, remove one of hydrogen will do the trick.
    Offline

    9
    ReputationRep:
    (Original post by ngwengsamowo)
    Name:  擷取.PNG
Views: 43
Size:  31.7 KB

    This is the third isomer I could find, is this correct?
    BDunlop has the correct answer above. The answer you wrote is not a tertiary alcohol, it is an ether.
    • Thread Starter
    Offline

    2
    ReputationRep:
    Thanks a lot
    Offline

    13
    ReputationRep:
    From the ER: "The structure should start with a cyclopentyl
    ring with an OH group and a methyl group on carbon atom 1. There is one carbon atom left to add.
    Cambridge International Advanced Subsidiary and Advanced Level
    9701 Chemistry June 2017
    Principal Examiner Report for Teachers
    © 2017

    If this carbon atom goes on carbon atom 2 of the ring as a methyl group we have a molecule with two
    chiral centres and therefore four isomers.

    If this carbon atom goes on carbon atom 3 of the ring as a methyl group we have a molecule with two
    chiral centres and therefore four more
    isomers, making eight so far.

    If this carbon atom goes on the methyl group already
    attached to carbon atom 1 this becomes an ethyl
    group. This molecule is not chiral, giving one more isomer, making nine. "
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: June 7, 2018

University open days

  1. Loughborough University
    General Open Day Undergraduate
    Fri, 21 Sep '18
  2. University of Cambridge
    Churchill College Undergraduate
    Fri, 21 Sep '18
  3. Richmond, The American International University in London
    Undergraduate Open Day Undergraduate
    Fri, 21 Sep '18
Poll
Which accompaniment is best?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.