Question

Piperazine, HN(C4H8)NH, is a diprotic weak base used as acorrosion inhibitor and an insecticide and has the followingproperties:

pKb1=4.22pKb2=8.67

For writing the reactions of this base in water, it can behelpful to abbreviate the formula as Pip:

Pip+H2OPipH++H2O??PipH++OH?PipH22++OH?

The piperazine used commercially is a hexahydrate with theformula C4H10N2?6H2O

What is the pH at the second equivalence point?