what is an active hydrogen ? how can we calculate the number of active hydrogen in a compound ? ( like if we were to find active hydrogen in 2-Propyne-1-ol )

ACTIVE HYDROGEN is nothing bur a hydrogen atom which is ready to donate electrons .Transfer hydrogenation is the addition of hydrogen (H2; dihydrogen in inorganic and organometallic chemistry) to a molecule from a source other than gaseous H2. It is applied in industry and in organic synthesis, in part because of the inconvenience and expense of using gaseous H2. One large scale application of transfer hydrogenation is coal liquefaction using "donor solvents" such as tetralin

zerewitinoff reaction ..............

reaction of grignard reagent with compound containing active/acidic hydrogen (hydrogen bonded with S,O,N , terminal alkyne)

Active Hydrogen is the hydrogen at allylic position which can easily be removed while elimination reactions