Chemistry of +1 iodine in alkaline solution

Thesis/Dissertation · Mon Jun 02 04:00:00 EDT 1958

DOI:https://doi.org/10.2172/932596· OSTI ID:932596

Chia, Yuan-tsan. ^[1]

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1. Univ. of California, Berkeley, CA (United States)

The iodine species formed either by adding hypochlorite to a basic iodide solution or by adding triiodide to sodium hydroxide, was identified as hypoiodite ion. The absorption spectrum of IO^- was investigated in the wavelength range from 450 mμ to 280 mμ. The kinetics of the reaction I^- + ClO^- = IO^- + Cl^- was studied spectrophotometrically in alkaline solution. The forward rate law was found to be d(IO^-)/dt = k(I^-)(ClO^-)/OH^-. At 25 C and an ionic strength of 1.00 M, k is 61 ± 3 sec^-. It was found spectrophotometrically that for certain ratios of the initial iodide to hydroxide concentrations, there was evidence of the presence of I₃^-, I₂OH^-, and I₂O^2- along with IO^-. The equilibrium constants between IO^- and these three species were evaluated by a graphical method. The formal potential of the cell: Pt:H₂:1 M NaOH : 1M NaOH, KI, NaIO : Au was found to be 1.297 v at 25 C. The equilibrium constant, K₂ = (I₃^-)(OH^-)^-2/(IO^-)(I^-)², of the reaction IO^- + 2I^- + H₂O ⇌ I₃^- + 2OH^- calculated from emf measurements agreed well with that from spectrophotometric measurements. The ionization constant of HOI was calculated to be 2.3 x 10^-11 at 25 C.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: US Atomic Energy Commission (AEC)
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 932596
• Report Number(s): UCRL--8311
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ABSORPTION SPECTRA
CHEMICAL REACTION KINETICS
DATA
HYDROXIDES
IODIDES
IODINE
IONIZATION