Question

NMR, the value of alkynyl proton is less than the value of alkenyl proton.

Answer 1

It is useful to compare and contrast H-NMR and C-NMR as there are certain differences and similarities:

13C has only about 1.1% natural abundance (of carbon atoms)12C does not exhibit NMR behaviour 13C nucleus is about 400 times less sensitive than H nucleus to the NMR phenomena Due to low abundance, we do not usually see 13C-13C coupling Chemical shift range is normally 0 to 220 ppm Chemical shifts measured with respect to tetramethylsilane,  (CH3)4Si  (i.e. TMS)Similar factors affect the chemical shifts in 13C as seen for H NMR Long relaxation times (excited state to ground state) mean no integrations