Potassium iodate

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Potassium iodate
Potassium iodate bottle sample.jpg
Potassium iodate sample and original bottle
Names
IUPAC name
Potassium iodate
Other names
Iodic acid, potassium salt
Properties
KIO3
Molar mass 214.001 g/mol
Appearance White solid
Odor Odorless
Density 3.89 g/cm3 (20 °C)
Melting point 560 °C (1,040 °F; 833 K) (decomposition)
Boiling point Decomposes
4.74 g/100 ml (0 °C)
9.16 g/100 ml (25 °C)
32.3 g/100 ml (100 °C)
Solubility Soluble in aq. KI solution
Insoluble in alcohol, liq. ammonia, ethyl acetate, ethylenediamine, hydrazine, conc. nitric acid
Vapor pressure ~0 mmHg
Thermochemistry
151.46 J·mol-1·K-1
-508.4 kJ/mol
Hazards
Safety data sheet Sigma-Aldrich
Flash point Non-flammable
Related compounds
Related compounds
Potassium chlorate
Potassium bromate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Potassium iodate in an inorganic compound with the formula KIO3.

Properties

Chemical

Potassium iodate is an oxidizer, though less powerful than its analogue potassium chlorate.

Heating it at high temperatures will cause it to decompose, releasing oxygen.

KIO3 → KI + 3/2 O2

Physical

Potassium iodate is a white solid salt, poorly soluble in cold water, but more soluble at high temperatures.

Availability

Potassium iodate is sold by chemical suppliers.

It is more commonly available in pill form, as protection against accumulation of radioactive iodine in the thyroid.

Like potassium bromate, potassium iodate is occasionally used as a maturing agent in baking.

Potassium iodate is sometimes used for iodination of table salt to prevent iodine deficiency.

Preparation

Potassium iodate can be prepared by adding iodine to a hot concentrated solution of potassium hydroxide.[1]

3 I2 + 6 KOH → KIO3 + 5 KI + 3 H2O

Since the iodate is much less soluble in cold water than hot water, it will precipitate out of the solution, upon cooling. The yields of this route are not great, however.

Oxidizing potassium iodide with a hot aq. solution of potassium permanganate will yield potassium iodate.[2]

Fusing potassium iodide with potassium chlorate or bromate will also yield potassium iodate. Refluxing a solution of iodine in conc. nitric acid with potassium chlorate will yield potassium iodate, in a better yield.

Neutralizing iodic acid with a potassium base, like hydroxide, carbonate or bicarbonate is a quick way of preparing this compound.

Projects

  • Oxidizing agent
  • Determination of hydrolyzable tannins in plants
  • Protection against radioactive iodine

Handling

Safety

Potassium iodate is an oxidizer. It may be harmful if ingested in large amounts.

Storage

In closed bottles, away from any flammable materials.

Disposal

Can be reduced to potassium iodide using a reducing agent, then the iodide recycled.

References

  1. https://www.youtube.com/watch?v=SNXIY4InWFU
  2. https://www.youtube.com/watch?v=tpWb0j78uGU

Relevant Sciencemadness threads