In this reaction you used observation of a precipitate as evidence that reaction
ID: 515179 • Letter: I
Question
In this reaction you used observation of a precipitate as evidence that reaction occurred. If there were no precipitate you would have had to isolate, purify and characterize the products of the reactions. This would have been a LOT OF WORK! But let's imagine that you did all of that for the reaction shown below, i.e. you isolated the iodide product of reaction of the bromide. Which analytical technique, mass spectrometry, infrared spectroscopy or proton NMR spectroscopy would you use to show that the iodide product is different from the bromide starting material, and that reaction occurred? Assume further that you don't have an authentic sample of the iodide product on hand to compare your spectra to. You need to show that the product is actually the iodide and not just that it is different form the starting bromide. Argue why the method you choose is best and why the other two methods are not as good.Explanation / Answer
Mass spectrometry will the ideal technique provided that the reaction is complete and the there is no starting material in the final product. The mass spectrum will only M+ peak for iodo compound but the starting material will have both M+ peak and M+2 peak of equal intensity due to the almost equal abundance of the bromine isotopes. Also the mass of these two will be different . Mass of iodo compound will be greater than the bromo compound.
In the case of IR we won't be able to predict the exact halide. We will only get the idea that it is a alkyl halide provided that you have a reference.
In NMR also we will get only the idea that some electronegative element is attached to carbon. But it is unable to predict which halogen without a reference nmr
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.