Overshooting the end point?

[malekv]

What is overshooting the end point, and what is the effect of it? How can it be prevented/made up for? 

[Panicmode]

When performing a titration, the aim is to burette in just enough so that the equivalence point it reached (the point at which all the substrate in the beaker has been neutralised/reacted completely with the buretted substance according to their mole ratio). Usually, this equivalence point is marked by a colour change of the mixture. We call the exact point at which this colour change occurs, the "end point". The end point is basically a very good estimate at the equivalence point (although it isn't always exactly the equivalence point) so we use this to help us determine when the substance in the beaker and the substance in the burette have reached the point where they have reacted in exact stoichometric ratios.


"Overshooting the end point", is an error that occurs when the person conducting the titration accidently goes over (or overshoots) this endoint by introducing too much of the substance from the burette into the beaker. Remember, the endpoint is the exact point at which the colour starts to change.

In overshooting the end point, you have added too much of the buretted liquid. This in turn means that later when you calculate the amount of substance in the beaker (using stoichometric ratios) it too will be larger than the actual amount.

Overshooting the end point can be prevented by ensuring that you are vigilant when performing the titration and that you don't have the burette nozzle turned on full pelt the entire time. We make up for overshooting the endpoint by performing multiple titrations and only using concordant titres.



Hope I helped