The concentration made was determined to be 0.0009946 M of Fe3+. The acid was made from diluting 41.3 mL of concentrated HCl in a 500 mL volumetric flask. Due to the large amounts of samples and standards, the acid solution was made multiple times.
Saturated Potassium Thiocyanate Saturated potassium thiocyanate was made in 100 ml volumetric batches. The solution was made from continuous addition of potassium thiocyanate to the flask until it stopped to dissolve in the solution. Since each batch of saturated solution contains different amounts of thiocyanate, sample sets were blanked with the corresponding thiocyanate solutions.
Time Duration For the time duration and wavelength determination, 5 mL of iron standard and 3 mL of saturated thiocyanate was mixed and diluted to 100 mL in a volumetric flask with 0.5 M HCl. The absorbance was read over a period of 2 hours at 30 min intervals.
Excess Reagent Standard iron solution was used and 0.5 M potassium thiocyanate was prepared. Following the reagent table below, the corresponding amounts of each reagent was added to 100 mL volumetric flask and diluted with water. The samples were analyzed with water as the