This SIR allows you to generate and plot titration curves, and then to simulate the titration. The analyte (unknown) may be a strong or weak acid or base with one or two dissociation constants. The titrant is always strong.
The titration curve is determined by parameters you choose from a menu at the left of the screen. You may alter the amount of analyte in millimoles, its solution volume in millilitres, the titrant concentration in mol/L, and the two dissociation constants. The first dissociation constant may range from 10-13 to 10. The second may have values from zero to one fourth of the first dissociation constant.
When you click on compute and plot curve, the computer plots the titration curve. You are provided with crosshairs, which you may use to explore the graph. You position them with the mouse and fine-positioned using the cursor keys.
Simulated titration
First, you must choose an indicator. As you click on the various indicators, the computer will fill the background of the titration curve with the two indicator colours,
You then fill the burette, and drain down to a reasonable starting point. You open and close the stopcock by clicking on the corresponding prompt on the menu, or near the upper and lower halves of the stopcock. Speeds may be varied from free-running to dropwise.
The read & record facility provides a magnifier, to enable you to read the burette to 0.01 or 0.02 mL, and a keypad which allows you to record your reading.
While you run the titration an Alberta wild rose moves along the titration curve, tracking pH as a function of volume of titrant delivered. The indicator colour change is realistically simulated. If you have chosen an indicator to produce a sharp end point, you will see flashes of the ultimate indicator colour as titrant is delivered several mL in advance, and may use this to control your speed of delivery.
The accuracy possible with this simulation is essentially that of good laboratory equipment. With suitable choice of indicator, you can determine end points to 0.03 mL or better.
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Updated July 25, 2000