To determine the strength of an unknown HCl solution by titrating it against a base (NaOH) using conductivity meter

Procedure

1. Standardization of NaOH solution:
   1. The burette is filled with intermediate NaOH solution.
   2. 10 ml of the oxalic acid is pipette out into a clean conical flask.
   3. Add 1-2 drop of phenolphthalein indicator.
   4. Titrate with NaOH solution till pink color appears which is end point, take concordant reading=A ml.


2. Conductometric titration:
   1. Switch on the conductivity meter, warm it up and adjust knob at room temperature. Calibrate the conductivity meter
   2. Take 50 ml of unknown HCl solution in clean beaker.
   3. Immerse the conductivity cell in the HCl solution so that the electrodes completely dip in solution.
   4. Take conductance of HCl
   5. Add 1 ml of NaOH solution from burette. Stir with help of glass rod and measure the conductance
   6. This process (addition of 1ml NaOH) is done till equivalence point is reached and a increase in conductance is observed after equivalence point (at least 10 readings)
   7. Plot the graph between the observed conductance values against the volume of NaOH added.
   8. The point of intersection gives the amount of NaOH required for neutralization of HCl= B ml. (graph)

Precautions

• After every addition of NaOH solution, the solution must be stirred thoroughly.
• Conductivity cell should be properly immersed in the solution.
• All precaution regarding the handling of the instrument should be taken.
• After completion of the experiment, the conductivity cell should be properly washed and dipped into distilled water.
• Temperature should be constant throughout the experiment.