What is the difference between sodium chlorate and sodium hypochlorite?

Sodium chlorate and sodium hypochlorite are common chemical raw materials, which are widely used. The names are one word apart, but the difference is huge, and in terms of price, sodium chlorate is more expensive than sodium hypochlorite.

Chemical Composition

Then there are some chemical differences. Sodium hypochlorite can oxidize iodide to I2 at any pH and sodium chlorate can only oxidize iodide at acidic conditions. You can take two solutions, add them directly to the potassium iodide solution, and the one that turns brown is sodium hypochlorite and the one that doesn’t change is sodium chlorate. Of course, the root of hypochlorite hydrolyzes, resulting in sodium hypochlorite being strongly alkaline; And chlorate root does not hydrolyze, so sodium chlorate solution is neutral, direct measurement of pH can also be identified.

Structural Differences

Chemical formula difference: sodium chlorate chemical formula is NaClO3, relative molecular weight 106.44. Usually white or yellowish isoaxial crystals. Salty and cool, soluble in water, slightly soluble in ethanol. In acidic solution has a strong oxidation, more than 300℃ decomposition of oxygen. Sodium chlorate is unstable. When mixed with phosphorus, sulfur and organic matter is impacted, it is easy to burn and explode, and easy to absorb moisture and agglomerate. It is mainly used to produce chlorine dioxide, sodium chlorite, perchlorate and other chlorate in industry .

Sodium hypochlorite is the most common “chlorine” bleaching agent used in home washing. Other similar bleaches are potassium hypochlorite, lithium hypochlorite or calcium hypochlorite, sodium hypobromate or sodium hypoiodate, chlorine-containing oxide solutions, chlorinated sodium trichosphate, sodium trichloroisocyanurate or potassium, but are generally not used in home washing. Bleach is a variant that destroys the hair color system or produces a chromophore.

Differences in Industrial Uses:

Sodium chlorate can be used as an oxidant or mordant in printing and dyeing industry. Inorganic industry as an oxidant, can also be used in the manufacture of sodium chlorite and perchlorate. Pharmaceutical industry used in the manufacture of pharmaceutical zinc oxide, sodium disulfide succinate. The pigment industry is used to manufacture advanced zinc oxide and Hualan. Used in agriculture as a herbicide. In addition, also used for papermaking, tanning leather. Ore treatment, seawater bromine extraction and manufacturing printing ink, explosives, etc.

Sodium hypochlorite is mainly used for disinfection in sewage treatment, but for some reason, there is more chlorine in the water, which is often called a carcinogen. When the water boils, you open the lid and keep it boiling for two or three minutes in order to let the remaining chlorine evaporate. Sodium hypochlorite in addition to bactericidal effect, there is also the removal of chroma, but for the mineral chroma brought by it cannot be removed, can only remove part of the organic chroma brought by the removal. In general, it is not recommended to use sodium hypochlorite in wastewater treatment, because the residual sodium hypochlorite will bring harm to the environment, as well as the toxicity to the biochemical system, and will affect the detection of COD, so that the COD data determined by potassium dichromate method is high due to the interference of chloride ions.

In fact, both sodium chlorate and sodium hypochlorite can be used in water treatment. In comparison, sodium hypochlorite has some disadvantages when used in water treatment, while sodium chlorate is more expensive, and both of them have their own advantages.

FAQ about Sodium Chlorate and Sodium Hypochlorite