Question

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

Answer 1

Alkenyl hydrogens are deshielded due to the movement of the electrons in the pi bond. Alkenyl hydrogens create an external magnetic field that is perpendicular to the double bond axis and causes the electrons in the pi bond to enter a circular motion. The circular motion of the pi bonds reinfornce the external field where the hydrogens are located thus being strongly deshielded and appearing low field in an NMR spectrum.
Hence, In NMR, the value of alkynl proton is less than the value of alkenyl proton