Question

why do some hydorgens appear higher upfield than others? what is the reasoning that is seen in NMR?

Answer 1

Upfield and downfield are terms used in 1H-NMR. when proton shifts comes in the region of 1ppm to 4ppm , it is called upfield. When it is 6ppm to 10ppm it is called downfield. The whole signal is based on the elevtron density around the proton under consideration. More the electron density around the H, more difficult will be to trace the H and thus magnetic strength has to be increased in order to get the H detected

ppm = (TMS freq - freq required)/(operating freq)

Thus TMS freq and operating are fixed.

More the frequency required to check the H, lower will be ppm value and more will be downfield signal.