Consider an experiment in which two burets, Y and Z, are simultaneously draining into a beaker that initially contained 275.0 mL of 0.300 M HCl. Buret Y contains 0.150 M NaOH and buret Z contains 0.250 M KOH. The stoichiometric point in the titration is reached 60.65 minutes after Y and Z were started simultaneously. The total volume in the beaker at the stoichiometric point is 655 mL. Calculate the flow rates of burets Y and Z. Assume the flow rates remain constant during the experiment.

Flow rate from buret Y is 2.061 ml/min

Flow rate from buret Z is 4.204 ml/min

Explanation:

The equation for the reactions are

NaOH + HCl → NaCl + H₂O

KOH + HCl  → KCl + H₂O

Total volume of Y and Z = Final volume in buret -  initial volume in buret

= 655 - 275 = 380 ml

Therefore we have

275 ml · 0.3 M HCl = V ·0.150MOH + (380 - V)0.25·MOH

Which gives

82.5 = 0.150V +95 -0.25V

From which V = 0.125 ml

Therefore 125 ml of NaOH was added in 60.65 minutes from buret Y with flow rate given by

125/60.65 = 2.061 ml/min

Also 380 - 125 or 255 ml of KOH was added in 60.65 minutes from buret Z with flow rate given by

255/60.65 = 4.204 ml/min.