Bleach: How does it DO that?

Bleach: Everyone’s favorite household cleaner

Bleach is something you probably have in your house right now. We use it very often, but many people don’t really understand how it works.

The active ingredient in bleach is sodium hypochlorite. Active ingredient just means that this is what makes bleach able to do things like disinfect, and bleach items. The other ingredients in bleach, water and sodium hydroxide, stabilize the sodium hypochlorite and keep it from breaking down into salt (NaCl) and Sodium Chlorate (NaClO₃). (1)

Figure 1. The chemical structure of sodium hypochlorite. (2)

How does bleach kill bacteria?

The sodium hypochlorite in the bleach attacks the bacteria’s proteins and causes them to clump together. (3) Bacteria need functioning proteins in order to live so when their proteins clump together it kills the bacteria because their proteins are no longer functional. However, some species of bacteria have a defense mechanism to try and protect themselves from sodium hypochlorite. Some bacteria have molecular chaperones such as Hsp33 or polyphosphate that take the clumped proteins, separate them, and then re-fold them into the correct shape. (4) 

This refolding allows the proteins to continue working so the bacteria don't die. 

This is why bleach doesn’t kill every single kind of bacteria. 

How does bleach bleach things?

On things that have colour, there are these things called chromophores. Chromophores are the parts of the molecule that make the substance have colour. (5)

What bleach does is it attacks the chromophore, and breaks the chemical bonds it has to the rest of the molecule so it doesn’t have the same colour as before. (5)

Don’t mix bleach with ammonia

Sodium hypochlorite reacts with ammonia to form the toxic chloramine gas. (6)

Chloramine gas can cause coughing, nausea, shortness of breath, watery eyes, chest pain, irritation to the throat, nose, and eyes and wheezing. (6)

References

 1. Powell Fabrication and Manufacturing Inc. (n.d.). Bleach Decomposition (Sodium Hypochlorite). http://www.powellfab.com/technical_information/sodium_hypochlorite/decomposition_reason.aspx (retrieved March 15, 2017)

2. Wikimedia Commons. (2006). Sodium hypochlorite.svg [image]. https://upload.wikimedia.org/wikipedia/commons/thumb/0/01/Sodium_hypochlorite.svg/1280px-Sodium_hypochlorite.svg.png (Retrieved February 18, 2017).

3. A., Thompson. (2008). How Bleach Kills Bacteria. Retrieved from http://www.livescience.com/3069-bleach-kills-bacteria.html (accessed March 6, 2017)

4. S., Reynolds. (2014). A., Thompson. (2008). How Bleach Kills Bacteria. Retrieved from https://publications.nigms.nih.gov/insidelifescience/bleach-vs-bacteria.html (accessed March 6, 2017)

5. G. D., Considine. Van Nostrand’s Encyclopedia of Chemistry, 5th edition.; John Wiley & Sons INC Publication: New Jersey, 2005

1.     6.   Washington State Department of Health. (n.d.). Dangers of Mixing Bleach with Cleaners. Retrieved from http://www.doh.wa.gov/YouandYourFamily/HealthyHome/Contaminants/BleachMixingDangers (accessed March 6, 2017)