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I want to get RRB Adv. Chemistry. I am Ok with buying all three subjects as well but it would be nice if I could buy Chemistry separately. Is it available anywhere(except the Reso website), second hand would also do.
Also if anyone knows, do they update it every year or it is same from a few years because there is one available here, but its from 2015.
Also I have the Mains one and haven't used them except for a few chapters so would be open to giving them to someone as well.
Let's hear the community's contribution
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So let’s say I’ve a -CxH2-CyOOH (carboxylic group, where x and y is the labelling of the carbon) versus -CzH2-O-O- (peroxy bond, z is the labelling of the carbon), is Cx or Cz more shielded? Does resonance affect anything, or does the second oxygen in the case of Cz even affect Cz since it’s not directly bonded?
Another related qn is if it’s -CxH2-COO-CyH2- (ester bond). Does Cx have higher shielding or does Cy have higher shielding?
Topic: NMR
Any help is greatly appreciated, thank you!
The explanation in the text book confuses me. How do all the non hydrogen atoms have a full octet in the structure on the right when the oxygen is a +1? The structure on the left has a central carbon on the left has a +1 charge so its octet is not full?
https://preview.redd.it/svufjcd7xe841.jpg?width=4032&format=pjpg&auto=webp&s=76ec76fc680965fb21b5d01392787d10d53ede3c
https://imgur.com/a/aFIu4zF
For the first one (#20), is their only two available structures? All I can see is switching the Oxygens around.
For the second (#15) I moved the cation around the first arene and then got stuck back in the original place on the right arene, but my professor said it was wrong.
They seem to be used interchangeably, but there has to be some sort of a difference; otherwise, we won't need to have 2 words as my English professor once told me.
Question https://i.imgur.com/NhlP9qP.png
This is what I have so far https://i.imgur.com/vrTKLsp.jpg
Hi Chem Help, I need some help or direction with some questions regarding structure determination from fragments and whatnot.
Basically the question is:
http://imgur.com/F7gYXNQ
A pure organic substance with molecular formula C11H15NO shows absorption in the UV spectrum and absorptions in the IR at 1680 & 1600 cm^-1 only. The 1H NMR spectrum of the subtance contains 5 signals:
| delta h | Integration and Multiplicity |
|---|---|
| 1.0 | 3 H (triplet) |
| 1.5 | 2 H (sextet) |
| 2.4 | 2h (triplet) |
| 3.2 | 3 H (singlet) |
| 7.3 | 5 H (multiplet) |
Determine the structure of the substance, giving reasons.
My Attempt/Thinking
Double Bond Equivalence = 11-(15/2) + (1/2) + 1 =5
UV absorbance therefore has conjugation
IR absorbance at ranges of 1680 and 1600 therefore C=O and C=C functional groups present
Assume Letters A-E for the above signals for simplicity's sake
A)
1.0 delta -> H-C-C-
3H -> CH3
Triplet -> Interacts with 2 other carbons
Hence signal A represents a CH3-CH2
B) delta 1.5 -> either H-C-C- or H-C-C=
2H -> CH2
Sextet -> interacts with 5 other hydrogens, CH3 on one side, CH2 on the other
Fragment B is a CH3-CH2-CH2
C) H-C-C= (delta 2.4)
CH2
triplet
therefore CH2-CH2
D) 3.2 -> H-C-X (X is electronegative)
3H singlet
Therefore CH3 with no adjacent hydrogens
E)
Indicative of a ring with one substitution.
Thats all I've got so far and I am stuck as to what to do next. If anyone could point me in the right direction, with either Videos or step by step websites, that would be amazing
We just started resonance in my OChem class, and I am sort of lost. I believe this molecule is called 1-methoxy-2-methyl-benzene, I was wondering if I did the resonance of it right, the ranking, and then the hybrid.
Heres a picture of what I have attempted.
http://i1070.photobucket.com/albums/u494/averagecollegestuden/20161008_203809_zps1ujq1w5q.jpg
If I am missing something, or am totally spacing, please tell me so I don't make the same mistake in the future.
)
