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My high-school chemistry teacher taught us the mantra "bases are slippery-soapy-slimy!"

This question and this answer in Quora say this is due to saponification - conversion of lipids from the top layer dead skin cells into a soap-like substance.

During some household cleaning I ended up with a small amount of a fairly strong solution of bleach in water between my thumb and forefinger and noticed it felt quite slippery, and it took several seconds of rubbing under water for it to stop.

In this case I would guess that saponification is not the explanation for the very slippery feeling. Is there another explanation?

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    $\begingroup$ Bases also hydrolize proteins, in oder words, they disolve slowly your skin therefore they feel slipery. $\endgroup$
    – Greg
    Mar 13, 2017 at 0:07
  • $\begingroup$ @Greg that sounds more like what I remember also - the same reason a caustic drain cleaner will "dissolve" or break down hair in a clogged drain. $\endgroup$
    – uhoh
    Mar 13, 2017 at 3:43
  • $\begingroup$ note: Info from the CDC as well as from phys.org, from Oregon State University and from Lenntech all have a lot to say on the chemistry of bleach as a disinfectant. $\endgroup$
    – uhoh
    Mar 13, 2017 at 4:36
  • $\begingroup$ I've just asked the related question Is it known for sure that bases feel slippery because of the production of soap/surfactant?. $\endgroup$
    – uhoh
    Mar 14, 2017 at 12:16

2 Answers 2

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Actually it is saponification. Bleach has alkali added to it, to stabilize it against decomposion to chlorine gas.

To wash your hands after contact with bleach was a wise move.

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    $\begingroup$ I didn't know that. It must be quite basic to feel so slippery. Fingers where not designed to to measure pH, I should look for some litmus paper to check my bleach some day. $\endgroup$
    – uhoh
    Mar 12, 2017 at 19:09
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    $\begingroup$ @uhoh Cabage will do it, too, and is easier to find (even a chemists household...) coolscience.org/CoolScience/Teachers/Activities/… $\endgroup$
    – Buttonwood
    Mar 12, 2017 at 20:40
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    $\begingroup$ Info from the CDC as well as from phys.org, from Oregon State University and from Lenntech all have a lot to say on the chemistry of bleach as a disinfectant. The last two say that NaOH${}^-$(aq) occurs naturally in hypochlorite solutions, rather than as an additive. $\endgroup$
    – uhoh
    Mar 13, 2017 at 4:35
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    $\begingroup$ @uhoh It would appear to depend on the specific formula you bought as to whether NaOH is added or not. The SDS for "Clorox Regular Bleach(1)" doesn't include any mention of sodium hydroxide, but the SDS their so-called "High Effiency Regular Bleach" and the SDS for "Splash-Less Regular Bleach" both include it. $\endgroup$ Mar 13, 2017 at 7:44
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    $\begingroup$ @uhoh Naturally you want to use bleach only in a well ventillated area with proper protection for yourself. As an example, using it as dilute warm aqueous solution to clean the shingle-covered walls of your housing (maybe typical not only in New Jersey ...), you hold your brush with a hand covered by a rubber / nitrile glove to protect your skin and you wear googles to protect your eyes from . And secondary, you won't mix two cleaners together, as some are able to "crack" the hypochlorite present in bleach, and eventually liberate toxic chlorine gas. $\endgroup$
    – Buttonwood
    Mar 13, 2017 at 10:52
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  • Maybe it needs to be clarified that the salt of a strong base and a weak acid can conduct saponification. Therefore the fact that bleach reacts with fatty acids creating soap, does not necessarily mean that bleach should be all just base (nor that something else other than saponification should be happening).

Household bleach is mainly sodium hypochlorite ($\ce{NaClO}$) dissolved in water (~<5%). One reason it works as a disinfectant is that it reacts with fatty acids of living organisms' membrane and turns them into soap.

$$\ce{NaClO (bleach) + R-COOH (fatty acid) → HClO + R-COONa (soap)}$$

(There are other mechanisms by which hypochlorite is known to perform disinfection, though the focus of this answer is to address how the slippery feeling comes about)

  • Why is soap slippery

The non-polar side of the soap molecule is less interactive with solid surfaces than polar substances such as water. Therefore soapy water flows with less friction on solid surfaces compared to water and is more slippery.

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  • $\begingroup$ I remember being taught in high school about protein hydrolyzation (as mentioned here) by strong basic solutions as well. Could interaction of bleach ingredients (hypochlorite or an added base) be doing this as well? $\endgroup$
    – uhoh
    Mar 13, 2017 at 4:18
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    $\begingroup$ Yes, it can destroy proteins as well. One way is sodium hypochlorite reacting with amine groups on protein, making amine chlorides and base. $\endgroup$ Mar 13, 2017 at 4:35
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    $\begingroup$ I've done some searching based on answers here, and just added some helpful links to discussions of the chemistry of bleach as a disinfectant in a comment below the question. $\endgroup$
    – uhoh
    Mar 13, 2017 at 4:38
  • $\begingroup$ There are two highly voted answers that are affirmative to saponification, but yours supports the idea that hypochlorite can lead to saponification without needing to invoke an additional base ingredient. $\endgroup$
    – uhoh
    Mar 26, 2017 at 15:13
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    $\begingroup$ @Kinformationist op asks as to why it is slippery , I,e why are soaps slippery but you have not mentioned about kindly look into it $\endgroup$
    – Chemist
    Apr 19, 2019 at 15:50

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