Analytical Chem - Lab Report Example

titrant volume. From the volume of titrant at the equivalence point weight of KI and KCl in the unknown solution was determined. Potentiometric titration is based on change in electrode potential with change in the ionic concentration during titration reaction. During titration reaction, there is decrease in the ionic concentration in a solution and this leads to decrease in electrode potential in accordance with Nernst Equation, which relates electrode potential with concentration of the ion in equilibrium with the electrode. 2. A silver nitrate solution containing 0.

9922 grams of AgNO3 in 100 mL of solution was used as the titrant. The titrant was handled carefully so as to protect the skin from it. Safety ware and hand gloves were used. 3. The 200L automatic pipette was calibrated for a 100L delivery with the analytical balance. This was done by recording the mass of 20 aliquots using analytical balance and then calculating the average mass and the standard deviation. This process was repeated until the relative standard deviation was brought down to less than 1%. 4. A set of 5 agar salt bridges containing 3% agar and 1% KNO3 in nanopure water were made.

The agar/salt/water mixture was heated in a microwave until the agar dissolved and the warm solution was injected into 10 cm lengths of plastic tubing. 5. An electrochemical cell was set up with a 24 well microplate. In one well 0.10 M solution of Cu(NO3)2 and a copper electrode was placed. In an adjacent well 1 mL of the titrant and a silver wire electrode was placed. The two wells were connected with a KNO3 salt bridge and the two electrodes were connected to the leads of the pH meter. The potential of the cell was measured. 6. The electrodes were disconnected and cleaned.

The 24 well plate on the balance was weighed on the balance. 1.00 mL of the unknown solution was added with the 1000L pipette to a well adjacent to the copper well, and