8. C3H8O The insert shows a single peak downfield that disappears when the sample is shaken with D2O. More extended coupling patterns are best analyzed from the outside in, i.e., start with the triplets. Note the location of triplet on the left. And the two triplets can't be coupled to each other, as then nothing could be coupled to the third peak. Also not the the answers to Problems 8&9 are isomers. 9. C3H8O This one has a typical coupling pattern you saw in lecture. Note the character of the peak on the far left-it looks a little too short and fat