When sodium hypochlorite is added to water, it forms an OCl- (hypochlorite) ion that is called free chlorine. This ion should not be confused with chlorine gas. Free chlorine is what most municipal water treatment facilities use for disinfection.
Sodium hypochlorite (NaOCl) is one of the chlorine types used in many households, including for water treatment. Apart from treating or degrading the toxins in water, it was also proven to kill other bacteria, such as Escherichia coli and total coliforms.
On the bottle's label, the concentration is typically expressed as a percentage. You would need to combine one part sodium hypochlorite with four parts water, for instance, if you had a 12.5% sodium hypochlorite solution and wanted to make a soft washing solution with a 1:4 mixing ratio.
Calcium hypochlorite decomposes in water releasing chlorine gas. Sodium hypochlorite solutions liberate the toxic gases chlorine or chloramine if mixed with acid or ammonia (this can occur when bleach is mixed with another cleaning product).
Sodium hypochlorite decomposes both to chlorate and chloride, and to oxjygen and chloride. The relation between these reactions was by no means clear, and the oxygen evolution had been relatively little investigated.
Calcium hypochlorite is a white solid that readily decomposes in water releasing oxygen and chlorine. It also has a strong chlorine odor. Neither compound occur naturally in the environment.
Higher exposures may cause a build-up of fluid in the lungs (pulmonary edema), a medical emergency, with severe shortness of breath. ► Exposure to Sodium Hypochlorite can cause headache, dizziness, nausea and vomiting.
Sodium and calcium hypochlorite can cause irritation of the eyes, skin, respiratory and gastrointestinal tract. Exposure to high levels can result in severe corrosive damage to the eyes, skin, respiratory and gastrointestinal tissues and can be fatal.
Bleach solutions will not be as effective after being mixed with water for over 24 hours.
Chlorine Bleach
Sodium hypochlorite reacts with ammonia, drain cleaners, and other acids. Many household products state that they contain bleach on the label.
When sodium hypo chlorite dissolves in water, two substances form, which play a role in for oxidation and disinfection. These are hypochlorous acid (HOCl) and the less active hypochlorite ion (OCl-). The pH of the water determines how much hypochlorous acid is formed.
Sodium hypochlorite: concentration and use:
Recommended dilution 1:100 dilution of 5% sodium hypochlorite is the usual recommendation. Use 1 part bleach to 99 parts cold tap water (1:100 dilution) for disinfection of surfaces.
It is safe to swim once your chlorine levels are around 5 ppm or after 24 hours. It is always best to test first! Muriatic acid can create a hot spot of acid in the water that could potentially burn or irritate your skin.
Using the fastest degradation rate (from the 1:12 dilution), 5.24% of available chlorine would be lost per year. The concentration of sodium hypochlorite would therefore remain above 90% of the initial concentration for 22.9 months.
The difference between sodium hypochlorite and bleach is in the consistency of the substance. Sodium hypochlorite is a powder that can be mixed with water to create bleach. Bleach, on the other hand, is liquid and is simply the finished product that is the result of combining powdered sodium hypochlorite and water.
The key difference between chlorine and sodium hypochlorite is that the chlorine (Cl2) is a pale yellow color gas whereas the sodium hypochlorite (NaOCl) is a greenish-yellow solid at room temperature. Chlorine and sodium hypochlorite are chemical compounds of the chemical element chlorine (Cl).
The hypochlorite ions react as an oxidising agent, similar to elemental chlorine. However, sodium hypochlorite and chlorine are not the same thing. Chlorine is an element, while sodium hypochlorite is a chemical compound that contains chlorine. Chlorine is a greenish-yellow gas that is highly reactive and corrosive.
Ecological Effects
Sodium and calcium hypochlorite are low in toxicity to avian wildlife, but they are highly toxic to freshwater fish and invertebrates. However, uses that result in point source discharges of hypochlorite-containing effluents are regulated through issuance of site-specific NPDES permits.
The hypochlorite accident is generally characterised by an initial reaction of the patient, while the pain, with marked oedema or bruising extending over the injured side of the face, cheek, or lips, may be immediate or delayed for several minutes or hours [13].
Sodium hypochlorite is a strong oxidizer. Oxidation reactions are corrosive. Solutions burn the skin and cause eye damage, especially when used in concentrated forms. As recognized by the NFPA, however, only solutions containing more than 40% sodium hypochlorite by weight are considered hazardous oxidizers.
When chlorine is added to water, it reacts with organic substances that occur naturally in the water. The compounds formed are called "disinfection byproducts (DBPs)." The amount formed depends on the amount of chlorine used and contact time between the organic substances and the chlorine.
What are the hazards? Bleach is an oxidizer and corrosive. Exposures may cause irritation or damage to the skin, eyes, and the respiratory tract. Vapors can cause serious discomfort or even acute distress requiring medical attention.