Question

Explain why the terminal alkyne has an acidic proton compared to alkane and alkene.

Answer 1

The electronegativity of the series F>O>N>C provides ample proof that the series HF, H2O, NH3, CH4 is decreasing acidity. And the acidity of the CH bond in CH4 is so small that we essentially ignore it. However, the CtriplebondH as a terminal group has a much high polarity than CH4 or double bonded C=H as a terminal group. The increased polarity of the triple bond is large enough that terminal CtriplebondH groups are stronger acids than those previously mentioned. Although a weaker acid that water, it still is strong enough to form salts with metals.