Procedure:

● This experiment requires a saturated calomel electrode and a platinum electrode. Wash the electrodes with double distilled water and dry them with filter paper.
● Pipette out 25 ml of the aqueous hydrochloric acid solution in a 250 ml beaker.
● To this beaker, add a pinch of quinhydrone to saturate the solution and stir the solution with the help of a glass rod.
● Dip saturated calomel electrode (reference electrode) and platinum electrode (indicator) in the beaker.
● Prepare 0.1 N sodium hydroxide solution (NaOH), by weighing 4gm of sodium hydroxide and mixing it well with double distilled water in a 1000 ml volumetric flask and further standardize it.
● Fill the burette with a standard solution of 0.1 N sodium hydroxide.
● Use a burette clamp to hold the burette.

● In the beaker with the given solution, add 2 ml of 0.1 N NaOH solution with the help of a burette.
● Stir the solution in the beaker with the help of a glass rod and measure the E.M.F.
● Repeat this process, add 2 ml of 0.1 N NaOH each time, and note EMF after every addition.
● After a few more additions, keep measuring the EMF. When the volume is approaching the equivalent point, reduce the volume of NaOH solution and start adding 1 ml installments from the burette.
● Continue for another 3-4 additions & note the EMF.
● Plot a graph between ΔE/ΔV and the volume of NaOH added.
● In the graph, the maximum of the curve represents the equivalence point.