new member Posted July 22, 2009 Report Share Posted July 22, 2009 Aren't ethers bent with a net dipole moment? I just did AAMC test 9 and couldn't figure out why MTBE (C4H9OCH3) can't H-bond with water. (Question 7) any idea? Link to comment Share on other sites More sharing options...
skp1187 Posted July 22, 2009 Report Share Posted July 22, 2009 haven't done the test yet but ethers are capable of H-bonding to water. Ethers can't H-bond with themselves Link to comment Share on other sites More sharing options...
sparkles3288 Posted July 22, 2009 Report Share Posted July 22, 2009 Ah yes, that Q. I did it by process of elimination. You knowfor sure they can both do dipole, van der waals, and covalent. That only leaves H-bonding. Also, pretty sure the O has to be accessible for H-bonding like it is with EtOH but not with MTBE. Thats my reasoning anyway. Link to comment Share on other sites More sharing options...
AG22 Posted July 24, 2009 Report Share Posted July 24, 2009 Ah yes, that Q. I did it by process of elimination. You knowfor sure they can both do dipole, van der waals, and covalent. That only leaves H-bonding. Also, pretty sure the O has to be accessible for H-bonding like it is with EtOH but not with MTBE. Thats my reasoning anyway. Hey guys, forgive me if I am wrong...and I think sparkles is saying what I'm going to say...but here's my clarfification: the thing to keep in mind wrt H-bonding is that the O, N or F atom MUST be bonded to a H atom itself....in which case, it can H-bond w/ itself..and to H-O-H. However, simply having R-O-R means that the oxygen does not have a H bonded to itself...as such it cannot H bond with itself... Now, my question is...can water H bond with ethers? the answer is...yes, it can. H-O-H is polarized, and H is delta +'ve as such, it will be attracted to the lone pairs (lps) of the oxygen on the ether. EDIT: Oh lol...okay I see the OP's dillema...I should read!! haha will probably help me w/ verbal So yeah...to the OP, that q is fked. That's soo odd....I'd do it the way sparkles did it...with POE. and maybe i'd make a note to be extra careful w/ questions of those types. sorry!! I thought i was helping :$ Link to comment Share on other sites More sharing options...
WaveSense Posted July 24, 2009 Report Share Posted July 24, 2009 No, AG22 you're exactly right I think. MTBE can not hydrogen bind because it has an O thats not bound to a H. Only those are able to undergo hydrogen bonding. Ethers are bent but that has nothing to do with whether hydrogen bonding can occur (at least as I remember) Link to comment Share on other sites More sharing options...
new member Posted July 24, 2009 Author Report Share Posted July 24, 2009 according to my princeton book, it does H bond with water! (just like alcohol) Link to comment Share on other sites More sharing options...
igeorgex Posted July 24, 2009 Report Share Posted July 24, 2009 I think the answer to that question was most likely referring to the 'degree' of H-bonding.. an alcohol can be an h-bond acceptor and donor (in that the H of an alcohol can bind to the O of water, and the O of an alcohol can bind to an H of water) whereas an ether can only be a hydrogen bond acceptor (it's O can bind to the H of water).. so the IMF for the alcohol wrt h-bonding >>> ether. but in either case, that question is pretty unfair (since both do undergo h-bonding) Link to comment Share on other sites More sharing options...
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