Question

Find the pH of the two equivalence points and the volume (mL) of 0.367M HNO3 needed to reach them in the titration of 0.188L of 0.250M ethylenediamine.

Answer 1

V1S1 = V2S2

V1 =? for HNO3

S1 = 0.367 M

V2 = 0.188 L for ethylenedimine

S2 = 0.250 M

Now, at equivalence point, the balanced equation is-

2HNO3 + (CH2)2(NH)2 = (CH2)2(NH3⁺)2][2NO3^-]

2 equivalents of HNO3 required for complete neutralization.

So, volume HNO3 required for the equivalence point = 0.188*0.250/(0.367/2) L = 0.256 L

Total volume = 0.188+0.256 =0.444 L

So, final concentration of ethylenediamine = 0.188*0.250/0.444 M =0.106

pKb1 and pKb2 are required for finding the pH