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Bleach and Chlorine
What Are the
Differences Between Bleach and Chlorine?
By Alex
Silbajoris
Bleach refers to many products with applications
ranging from whitening laundry to killing germs to making paper.
Bleaches work by altering chemical compounds,
either adding oxygen by the process called oxidation, or by removing oxygen by
the process called reduction.
Chlorine is a component of some kinds of
bleaches, though not all of them.
TL; DR (Too Long; Didn't Read)
Chlorine is a chemical element present in many
bleach compounds. Common bleach is a solution of sodium hypochlorite in water,
with other kinds also widely available.
Properties of Elemental Chlorine
Heavier than air, chlorine is a pure chemical
element, a greenish-yellow gas that readily combines with most other elements.
It is toxic in small concentrations, especially
with longer exposure times.
Chlorine gas reacts with moisture in the
respiratory system to create hypochlorous and hydrochloric acids on tissues,
along with oxidants and enzymes that break down proteins.
When a chlorine atom gains an electron, it
becomes chloride, a stable ion that exists in ionic bonds with positive ions
such as sodium, potassium and calcium.
Properties of Chlorine in Bleach Products
Common household laundry bleach is sodium
hypochlorite, NaOCl, diluted in water to a 3 - 6 percent solution.
Other solutions of sodium hypochlorite find
applications from bleaching paper to sanitizing medical and food preparation
equipment to water treatment.
It's an eye and skin irritant, which is why
swimming pool water can make your eyes burn.
When mixed with ammonia, bleach releases
chloramine gas, which is extremely toxic. (If you ever accidentally mix ammonia
and bleach, leave the room immediately and call 911 or at least poison
control.)
When mixed with acids, it releases elemental
chlorine gas.
Bleaches Work Through Oxidation or Reduction
As whiteners, bleaches break down chromophores,
which are groups of atoms that absorb some wavelengths of light and reflect
others.
Those reflected wavelengths are the colors we
see in pigments.
Bleach breaks down these compounds through
oxidation, a chemical reaction that involves taking away electrons from
neighboring molecules.
These processes also kill germs by breaking down
cell proteins and destroying internal cellular structures.
Other Bleaches Without Chlorine
There are many compounds that can be used as
bleaching agents that do not use chlorine.
Other oxidizers include hydrogen peroxide,
sodium perborate, sulfur dioxide and sodium bisulfite.
Even light can be an oxidizing agent, which is
why many colors fade after long exposure to sunlight.
Reducers include sodium and zinc dithionite,
sulfites, and sodium borohydride. Some of these reducing bleaches serve to
remove oxides such as rust, which is iron oxide.
An
ecological blogger, technical writer and trainer, Alex Silbajoris also leads a
nonprofit watershed group. He is an avid gardener and cook. He holds a
bachelor's degree in English and a master's degree in journalism, from The Ohio
State University. Other studies include geology and biological sciences
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