[bio775]

I am having difficulty understanding it.

Molecule B (I have attached a screen shot of the IR spectrum reading)

1)Which types of bonds can be identified in the IR spectrum of molecule B?   
a) C=O and O-H
b) C=O and C=C   
c) C=O only
d) O-H only

2)By identifying the molecular ion, determine which of the molecular formula is consistent with the mass spectrum of B.   
a) C4H8O2   
b) C2H3O
c) C2H4O
d) C4H6O

3) How many carbon environments are there in molecule B?   
a) 4   
b) 11   
c) 10   
d) 3

4) The peak at 25 ppm in the 13C NMR spectrum of B is most likely to be?

5)The peak at 207 ppm in the 13C NMR spectrum of molecule B is most likely to due to the C atom in which functional group?

6) Identify molecule B.

Molecule C (I have attached a screen shot of the IR spectrum reading)

1) The UV/Visible spectrum of molecule C shows a strong absorption peak around 270 nm.

Use this information and its mass, IR and 13C NMR spectrum to identify the identity of molecule C.

Please answer as much as you can. Thanks.

[orgopete]

Just so you don't run afoul of the forum rules, how many peaks are present in the 13C spectrum? Can you answer your third question?  Do something similar to the other questions. You may then reason some parts of the problem and ask if you are correct so far.

[bio775]

Sorry if I broke the rules. I should have asked for help explaining how it works rather than answers. I did spend sometimes reading some notes online but still find it difficult to understand it. How do u figure out the molecular formula? Also I thought answer for molecular B for Q 1 is C=O and C-H but it isn't in the list. So, is it just C=O? but why?

[orgopete]

The point of the rules is that we are going to do everyone's homework assignments.

Let's start with question three. Look at the 13C spectrum. How many carbons are present? Does that help you to answer question 2? What is the MW (look at the mass spectrum)? Which answers of question 2 has the correct MW?

[bio775]

How do u figure out how many C are present by looking at the 13C spectrum? Also how do u figure out the molecular weight? Sorry this is totally new to me and I am willing to learn if u can guide me through.

[orgopete]

This is pretty elementary. If you have a book or are taking a class, it will explain this. In this case, how many peaks do you see (hint, there are 4)? Each unique carbon has a peak. How many carbons are there?