I really do not understand why on A the methyl groups are the same but on B the
ID: 927267 • Letter: I
Question
I really do not understand why on A the methyl groups are the same but on B the methyls on the same side are different and on C why all the methyls are the same. All of these seem to contradict each other which is leaving me very confused on how to answer these properly.
http://www.saplinglearning.com/ibiscms/mod/ibis/vi ,University of California-Irvi saplinglearning.com saplinglearning.com File Edit View Favorites Tools Help Pokémon Showdown! bat. O sapling Electronic Home. Chem ILD F15-Elizabeth. . Sapling Learning ekd1rdik203y8 O writing 39C Argument & D Turnitin M Lab & Master ng Sign In Attempts Score ignment Print Calculator Periodic Table Available From12/1/2015 06:00 PM Due Date: Points Possible: 100 Grade Category: Graded Question 11 of 26 Incorrect rrctSolution 12/7/2015 11:55 PM Map sapling learning 3 How many unique H NMR and 13c NMR signals exist for each compound? CH3 H3C a CH3 H3C CH3 Policies: Homework ou can check your answers CH3 H3C CH3 H3C H3C CH3 You can view solutions when you complete or give up on any question 98 H NMR signals You can keep trying to answer each question until you get it right or give up. Number Number Number Number You lose 5% of the points available to each answer in your question for each incorrect attempt at that answer 9 10 13C NMR signals Help With This Topic Web Help & Videos Technical Support and Bug Reports Number Number Number 12 13 Previous ? View Solution 0 Check Answer NextExit 15 Explanation Copyright © 2011-2015 Sapling Learning, Inc.-19 about us careers partners privacy policy terms of use contact us help 8:40 AM .ill 12/7/2015Explanation / Answer
In compound A both the methyl groups are identical because passing a plane through the a and b carbons both upper side part and lower side parts are mirror images to each other therfore both are same
In compound B all the methyl groups are different, because all the symmetry elements are abscent (i,e plane, axis and inversion centre etc).
In compound C all the methyls are same, because centre of invertion symmetry element is present.
in compound D all are equal because all symmetry elements are present.
you can imagine once in a proper way you can get.