Answer:
NMR (Nuclear magnetic resonance) is modern spectroscopy technique to study a variety of nuclei for e.g. 1H NMR, 2H NMR, 13C NMR, 15N NMR, 19F NMR etc
When any nuclei is place in any external magnetic field it starts spinning according to flamings right hand rule & the angular frequency of nuclei is called as Larmor Frequency (ω), and the charged nuclie generates oscillating electric field . There are two energy states Alpha state and Beta state depending on the alignment of spinning nuclie.
If radiowave of frequency (ω) is supplied to the operation the two electric field couples and energy gets absorbed by the nucleus this process is known Resonance.
Depending on the environment of all protons, not all protons absorbs the same amount of energy and the protons are shielded by electrons from the external magnetic field.
Tetramethylsilane (TMS) is used for 1H and 13C NMR, have the delta shift value of 0 PPM
[tex] \sf \: \delta \: shift = \frac{shift \: from \: TMS \: in \: Hz}{spectrometer \: frequency \: in\: MHz} [/tex]
The number of signals of any compound depends on the chemical shift, at every specific shift NMR shows a signal.
Let's understand step by step:
Consider the simplest organic molecule in Organic chemistry methane, methane have only one carbon atom hence it shows only One 13C NMR signal.
Let's move to ethane, ethane have two carbon atoms but the environment of both carbon atom are same that they are terminal carbon bounded to 3 H atoms each. since the chemical environment of both the Carbon atom is same it will again show only One 13C NMR signal.
Now coming to propane, propane have three carbon atoms, two on terminal (methyl groups) and one that is in middle touching both the carbon atoms, the Chemical environment of terminal two carbons are same so they both together will show one peak and the middle carbon(-CH2 group) have different environment so it will show the signal at different shift. Hence the total number of 13C NMR signal would be two!
Thanks for joining brainly community!
