# laundry bleach vs hydrogen peroxide **URL:** \ **Category:** Factual Questions\ **Created:** [January 23, 2004, 9:20am UTC](https://boards.straightdope.com/t/laundry-bleach-vs-hydrogen-peroxide/225741 "2004-01-23T09:20:58Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![ccwaterback](https://avatars.discourse-cdn.com/v4/letter/c/df705f/32.png) [@ccwaterback](https://boards.straightdope.com/u/ccwaterback)\ **Post date:** [January 23, 2004, 9:20am UTC](https://boards.straightdope.com/t/laundry-bleach-vs-hydrogen-peroxide/225741/1 "2004-01-23T09:20:58Z")
Are laundry bleach and hydrogen peroxide related in some way? Can one be substituted for the other? Seems to me they share some of the same properties. What’s the deal? ---
**Author:** ![scm1001](https://avatars.discourse-cdn.com/v4/letter/s/c4cdca/32.png) [@scm1001](https://boards.straightdope.com/u/scm1001)\ **Post date:** [January 23, 2004, 11:23am UTC](https://boards.straightdope.com/t/laundry-bleach-vs-hydrogen-peroxide/225741/2 "2004-01-23T11:23:58Z")
there are several types of laundry bleach. Chlorine containing (smells like swimming pools) non-chlorine containing (often percarbonates or similar). Both sort of work the same way (reacting with coloured substances making them noncoloured) but they are quite different chemistry. You are right, percarbonates and hydrogen perxide are similar but not identical. Percarbonates are a solid soluble salt where the peroxide has been “locked up” in the salt structure. They often do the same reaction, but in a slightly different way. ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [January 23, 2004, 3:35pm UTC](https://boards.straightdope.com/t/laundry-bleach-vs-hydrogen-peroxide/225741/3 "2004-01-23T15:35:09Z")
Classic chlorine-containing laundry bleach consists of an aqueous solution of sodium hypochlorite (NaClO). Hydrogen peroxide has the formulas H[sub]2[/sub]O[sub]2[/sub] and for household use, is generally supplied as a 3% aqueous solution. Both chemicals are oxidizing agents. They tend to oxidize other chemical species. They work as bleaches since many colored compounds, such as dyes, tend to be colorless when oxidized. Both chemicals also function as disinfectants, since infectious agents are killed by the oxidizing action of these chemicals. **scm1001** , I would not characterize their chemistry as being “quite different.” What makes you say this? Also, who brought up “percarbonates\*”? \*better known as “carbonate peroxyhydrates” ---
**Author:** ![Annie-Xmas](https://avatars.discourse-cdn.com/v4/letter/a/ecc23a/32.png) [@Annie-Xmas](https://boards.straightdope.com/u/Annie-Xmas)\ **Post date:** [January 25, 2004, 1:31pm UTC](https://boards.straightdope.com/t/laundry-bleach-vs-hydrogen-peroxide/225741/4 "2004-01-25T13:31:21Z")
Laundry bleach is a combination of washing soda (sodium carbonate) and chloride of lime. It is very toxic and cannot be combined with ammonia or acids. I consider it downright nasty, and wonder why anyone uses it. Hydrogen peroxide is a milder bleach and much, much safer. The two basic oxygen bleaches are sodium perborate, a combination of hydrogen peroxide and borax, and sodium percarbonate, a combination of hydrogen peroxice and washing soda. Lemon juice and vinegar can also be used to bleach clothes, as can sunlight. ---
**Author:** ![scm1001](https://avatars.discourse-cdn.com/v4/letter/s/c4cdca/32.png) [@scm1001](https://boards.straightdope.com/u/scm1001)\ **Post date:** [January 25, 2004, 5:59pm UTC](https://boards.straightdope.com/t/laundry-bleach-vs-hydrogen-peroxide/225741/5 "2004-01-25T17:59:07Z")
> [@robby](#): > > **scm1001** , I would not characterize their chemistry as being “quite different.” What makes you say this? Also, who brought up “percarbonates\*”? > > " The chemistry of peracids and chlorine in bleaching effectively involves attacking coloured species. These coloured species are usually aromatic or contain double bonds. To a chemist (i.e me) these two chemicals have quite different way of attacking these compounds and reactivity profiles - however to a layman they both just attack coloured stuff. As to who brought up percarbonates – the OP did in asking about bleaches which included percarbonates ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [January 29, 2004, 10:56pm UTC](https://boards.straightdope.com/t/laundry-bleach-vs-hydrogen-peroxide/225741/6 "2004-01-29T22:56:23Z")
> [@Annie-Xmas](#): > > Laundry bleach is a combination of washing soda (sodium carbonate) and chloride of lime. It is very toxic and cannot be combined with ammonia or acids. I consider it downright nasty, and wonder why anyone uses it. > > Hydrogen peroxide is a milder bleach and much, much safer. Laundry bleach consists of a 4-6% aqueous solution of sodium hypochlorite. Sodium hypochorite is produced today by reacting chlorine gas and sodium hydroxide. **Annie** , if you are using archaic terms like “chloride of lime,” I wonder where you are getting your information from. As far as the safety and “mildness” of hydrogen peroxide, it depends on what concentration of hydrogen peroxide you are talking about. A 3% aqueous solution of hydrogen peroxide is fairly innocuous (as long as it is not swallowed or splashed into the eyes), but for a 30% solution or higher, you are talking about a very dangerous substance. (Unlike sodium hypochlorite, which in its pure form is a relatively innocuous solid salt, pure hydrogen peroxide is a liquid.) Here are some highlights from various Material Safety Data Sheets for hydrogen peroxide: > [@](#): > > Very concentrated solutions and pure hydrogen peroxide, as opposed to dilute solutions, are dangerous and should not be handled without expert instruction. > [@](#): > > EMERGENCY OVERVIEW > Danger! Strong oxidizer. Contact with other material may cause a fire. Harmful if inhaled. Corrosive. Causes eye and skin burns. May cause severe respiratory tract irritation with possible burns. May cause severe digestive tract irritation with possible burns. > [@](#): > > Stability: Unstable - readily decomposes to water and oxygen. Light sensitive. May develop pressure in the bottle - take care when opening. Forms potentially explosive compounds with ketones, ethers, alcohols, hydrazine, glycerine, aniline, sodium borate, urea, sodium carbonate, triethylamine, sodium fluoride, sodium pyrophosphate and carboxylic acid anhydrides. Materials to avoid include combustibles, strong reducing agents, most common metals, organic materials, metallic salts, alkali, porous materials, especially wood, asbestos, soil, rust, strong oxidizing agents. Sources: [http://www.bu.edu/es/labsafety/ESMSDSs/MSHydPeroxide.html](http://www.bu.edu/es/labsafety/ESMSDSs/MSHydPeroxide.html) [http://ptcl.chem.ox.ac.uk/MSDS/HY/hydrogen\_peroxide\_30pc.html](http://ptcl.chem.ox.ac.uk/MSDS/HY/hydrogen_peroxide_30pc.html) ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [January 29, 2004, 11:03pm UTC](https://boards.straightdope.com/t/laundry-bleach-vs-hydrogen-peroxide/225741/7 "2004-01-29T23:03:31Z")
> [@scm1001](#): > > The chemistry of peracids and chlorine in bleaching effectively involves attacking coloured species. These coloured species are usually aromatic or contain double bonds. To a chemist (i.e me) these two chemicals have quite different way of attacking these compounds and reactivity profiles - however to a layman they both just attack coloured stuff. I see. I wasn’t thinking much beyond “both are oxidizing agents.” If you are going to get into chemical mechanisms, though, I defer to your expertise. ---
**Author:** ![ccwaterback](https://avatars.discourse-cdn.com/v4/letter/c/df705f/32.png) [@ccwaterback](https://boards.straightdope.com/u/ccwaterback)\ **Post date:** [January 30, 2004, 12:02am UTC](https://boards.straightdope.com/t/laundry-bleach-vs-hydrogen-peroxide/225741/8 "2004-01-30T00:02:58Z")
I guess I was just wondering, since peroxide isn’t toxic, why do they use bleach in cleaning solutions rather than peroxide? ---
**Author:** ![CrazyCatLady](https://avatars.discourse-cdn.com/v4/letter/c/dfb087/32.png) [@CrazyCatLady](https://boards.straightdope.com/u/CrazyCatLady)\ **Post date:** [January 30, 2004, 12:21am UTC](https://boards.straightdope.com/t/laundry-bleach-vs-hydrogen-peroxide/225741/9 "2004-01-30T00:21:48Z")
Well, my understanding is that peroxide _is_ toxic, at least in concentrations that are effective for bleaching. (I use 3% peroxide on my scrubs all the time to remove bloodstains, and have never yet seen as much as a lightish patch, much less a bleached spot.)