LAB REPORT

Comparison of methods available for end-point detection for acid-base titrations

Comparison of methods available for end-point detection for acid-base titrations

Introduction

Titration is a laboratory technique by which we can use to determine the concentration of an unknown solution using a standard concentration of another solution that chemically reacts with the unknown. This standard solution is referred to as the "titrant". We have to have some way to determine when the reaction is complete so you add indicator to the unknown so you can see when the reaction is complete. This is referred to as the "end point" or more technically the equivalence point. At that point the entire unknown has been reacted with the standard titrant and some kind of chemical indicator must let us know when that point has been arrived at (Coyne, 2005, pp. 44).

Generally we know the morality of the titrant since it is a standard solution. We also pre-measure the volume of the unknown. We then titrate with the standard from a burette into the container with the measured unknown and the chemical indicator until the indicator either turns color or a precipitate indicates that the end point or the equivalence point has been reached. Having the initial and final readings of the titrant burette gives us the volume of the titrant used. The only unknown in the above equation is the Normality of the unknown.

Procedure

A typical titration begins with a conical flask containing a precisely known volume of the reactant and a small amount of indicator, placed underneath a w: burette containing the reagent. By controlling the amount of reagent that is added to the reactant, it is possible to detect the point at which the indicator changes color (Prichard, 2003, pp. 10). As long as the indicator has been chosen correctly, this should ...