Difference between revisions of "Sodium chlorate"

Revision as of 11:53, 4 August 2015

Sodium chlorate is an inorganic compound, comprised of equal numbers of sodium cations and chlorate anions, giving it the fomula NaClO₃.

Properties

Chemical

It is a strong oxidizing agent, easily supplying oxygen to combustibles. It decomposes above 300 °C yeilding oxygen and sodium chloride.

2 NaClO₃ → 2 NaCl + 3 O₂

Sodium chlorate will react with potassium chloride to precipitate potassium chlorate:

KCl + NaClO₃ → NaCl + KClO₃

Physical

Sodium chlorate is a colorless or white crystalline solid with a cubic crystal structure. It is soluble in water, methanol, glycerol, hydrazine and slightly soluble in ethanol and ammonia. Because sodium chlorate is hygroscopic, potassium chlorate is often preferred for use as an oxidizer.

Availability

It can be bought as "weed killer" at a hardware store, or it can be bought online. Many countries, however, have banned sodium chlorate weed killers.

Preparation

Sodium chlorate can be produced by boiling bleach, which causes it to disproportionate into sodium chlorate and sodium chloride.

A more efficient way of producing sodium chlorate is via the electrolysis of a supersaturated sodium chloride solution with an appropriate anode at ~5 volts DC.

Although the exact reactions are very complex, the basic overall equation is:

NaCl + 3 H₂O → NaClO₃ + 3 H₂

Projects

• Preparation of potassium chlorate
• Make a dry chemical oxygen generator: Heat is generated by oxidation of a small amount of iron powder mixed with the sodium chlorate, and the reaction consumes less oxygen than is produced. Barium peroxide is used to absorb the chlorine which is a minor product in the decomposition.^[1] An ignitor charge is activated by pulling on the emergency mask. Similarly, the Solidox welding system used pellets of sodium chlorate mixed with combustible fibers to generate oxygen.

Handling

Safety

Powerful oxidizer! Fire hazard! Keep away from any flammables.

Due to its oxidative nature, sodium chlorate can be very toxic if ingested. The oxidative effect on hemoglobin leads to methaemoglobin formation, which is followed by denaturation of the globin protein and a cross-linking of erythrocytemembrane proteins with resultant damage to the membrane enzymes. This leads to increased permeability of the membrane, and severe hemolysis. The denaturation of hemoglobin overwhelms the capacity of the G6PD metabolic pathway. In addition, this enzyme is directly denatured by chlorate reducing its activity.

Storage

Sodium chlorate should be stored in closed bottles, away from any flammable materials and strong acids. Since it's hygroscopic, it should be kept in a dry place.

Disposal

Sodium chlorate can be neutralized with sodium or potassium metabisulfite.

References

1. ↑ http://en.wikipedia.org/wiki/Sodium_chlorate#cite_note-8

Relevant Sciencemadness threads

• Sodium chlorate production questions