Ethyne (HC≡CH) has a pKa

Ethyne (HC≡CH) has a pKa value of 25, water has a pKa value of 15.7, an ammonia (NH3) has a pKa value of 36. Draw the equation, showing equilibrium arrows that indicate whether reactants or products are favored, for the acid-base reaction of ethyne with

a. HO−
c. Which would be a better base to use if you wanted to remove a proton from ethyne, HO− or −NH2?