Answer: -
1.8
End point passed.
Explanation: -
Volume of HI solution = 47.0 mL = 0.047 L
Strength of HI solution = 0.47 M
Since HI is a strong acid, all of HI will dissociate to give H +.
[H+ ] =0.47 M x 0.047 L
= 0.02209 mol
Volume of KOH = 25.0 mL = 0.025 L
Strength of KOH = 0.25 M
Since KOH is a strong base, all of KOH will dissociate to give OH-.
[OH-] = 0.25 M x 0.025L
= 0.00625 mol
Since [H+] and [OH-] react to form water,
[H+] unreacted = 0.02209 – 0.00625 = 0.01584 mol
Using the formula
pH = - log [H+]
= - log 0.01584
= 1.8
As the strong acid HI is being titrated by strong base KOH, the pH at the end point should be 7.
The pH has already crossed that. Thus the titration end point has already passed
