00:01
In this problem, we're looking at a carbon -13 nmr spectrum, and we want to say which of the five hidden structures is consistent with this.
00:13
And here you don't even need to be all that familiar with carbon 13.
00:18
So we can tell that there's three signals.
00:21
And each signal is going to come from a chemical environment.
00:27
So we'll go through our structures and figure out how many signals.
00:31
We should have for each and that will often eliminate quite a few of your options in these kinds of questions and then at the end if we have to make a decision between two or three we can do that so structure one here every carbon has a different environment so even though these are both ch3 groups well this is next to a ch2 group this is next to a ch group with a chlorine so these are different so total will have four signals so we can eliminate one.
01:06
When we look at two, each methyl group here is exactly the same.
01:10
So they'll be in the same signal.
01:12
And then we'll have a different one here.
01:14
So that's two signals...