Piperazine, HN (C_4H_8) NH, is a diprotic weak base used as a corrosion inhibito
ID: 1054067 • Letter: P
Question
Piperazine, HN (C_4H_8) NH, is a diprotic weak base used as a corrosion inhibitor and an insecticide and has the following properties: p_Kb1 = 4.22 pKb_2 = 8.67 For writing the reactions of this base in water, it can be helpful to abbreviate the formula as Pip: The piperazine used commercially is a hexahydrate with the formula C4H10N2 -6H20. What is the initial pH of the solution, before any titrant is added? Express your answer numerically with two digits after the decimal point. The percent neutralization points for a titration indicate the percent of the reagent that has reacted. For example, at the 25% neutralization point for piperazine, 75% (0.75 Times [Pip]) of the base remains, and 25% is neutralized to form PipH^+. Calculate the pH at the 25%, 50%, and 75% neutralization points of the first neutralization, respectively. Enter the pH at the 25%, 50%, and 75% neutralization points to two decimal places separated by commas. What is the pH at the first equivalence point? Express your answer numerically with two digits after the decimal point.Explanation / Answer
Initial pH = 11.23
25 % neutralization=10.26
50% neutralization = 9.78
75 % neutralization = 9.30
First equalence point = 7.56