Question

DH Volume Trial 1.9 1.9 1.9 1.9 220 3.7 4.1 4.6 49 4.2 4.9 5.3 55 10.6 10,6 10.6 10.6 10.6 10.6 10.6 106 10.6 106 106 10.6 10.6 105 106 calculations for : concentration, pka and Ka. Thank you! concentrantion is 0.1M

Answer 1

In trial 2 and trial 3 we see a jump in the pH at the volume of titrant= 10 mL

So, the equivalence point of the titration is= 10 mL

So the half equivalence point of the titration is= 5 mL

The value of pH at 5 mL of titrant are: 3.7, 4.2 and 3.9

So the average pH value= (3.7+4.2+3.9)/3 = 3.93

So, as the pH value at half equivalence point is equal to the pKa of the acid so the pKa value of the acid will be= 3.93

And as pKa= -log₁₀[Ka]

so, Ka=10^-pKa

So the Ka value will be, Ka= 10^-3.93 = 1.175X10^-4

So the pKa value of the acid is 3.93 and Ka value is 1.175X10^-4

And the concentration is given to be 0.1 M