TITRATION Andy Park

What is Titration? A method of quantitative chemical analysis used to calculate concentration A known concentration and volume of titrant reacts with a solution of analyte or titrand to determine the conentration. How titration works: When the base or acid of known concentration meets with the unknown acid or base, the pH slowly changes By calculating how much acid reacts with how much base, we can find out the concentration of the unknown. ACID + BASE = WATER + SALT

SETUP

PROCEDURE Titration begins with a beaker or a Erlenmeyer flask containing a precise volume of the analyte with a small amount of indicator placed Then the analyte is placed under a calibrated burette containing the titrant Small values of the titrant are added to the analyte When the indicator changes color, that marks the end of the titration

Types of Titration Acid – Base Redox Gas-Phase Complexometric Zeta potential Mainly Used Choose the right indicator

TIPS When using large quantities of both titrant and unknown, you can quickly finish the first experiment, giving you a simple idea of where the color changes Even if the experiment was perfect in the first trial, repeat to reduce error Make sure the walls of the beaker or flask doesn’t contain unreacted titrant during the experiment, this can be fixed by running deionized water on the walls of the flask. Small amounts of water will not change the outcome of the titration Label the unknown and titrant so you don’t mix up the data table Bubbles in the burette tip can usually be removed by tapping the side of the burette while the stopcock is open Placing something white can help with spotting the color change

SAMPLE QUESTIONS You have a 25 mL solution of 0.5 M NaOH It is titrated until neutralized into a 50 mL sample of HCl Determine the concentration of HCl A mL sample of acetic acid is titrated with mL of M NaOH Determine the molarity of the acetic acid