Kodak ECN-0002/1 Processing KODAK Motion Picture Films, Module 3, Analytical Proc edures H24.03 9, Sodium Sulfite (Na2SO3):, Thiosulfate (S2O3, Hypo Index (HI) or Total Reductants:, ):

Processing KODAK Motion Picture Films, Module 3, Analytical Proc edures • H24.03 9
Example Potentiometric Calculations:
Hypo Index (HI) or Total Reductants:
Thiosulfate (S2O3
=
):
Sodium Sulfite (Na2SO3):
Titration mL 0.1 N Na2S2O3 Titrant
Blank A = 40.50
Sample A = 21.85
Blank B = 40.55
Sample B = 19.80
HI (1), mL = (40.50 – 21.85)(0.0989)
0.1000
= 18.4 mL 0.1000 N I2
g/L S2O3
=
=(40.55 – 19.80)(0.0989)(112.13)(1000)
(2.0)(1000)
= 57.5 g/L
g/L Na2SO3=[(40.50 – 21.85)(2.0) – (40.55 – 19.80)](0.0989)(63.02)(1000)
(2.0)(1000)
= 51.4 g/L