# Exothermic Reaction

**URL:** <https://boards.straightdope.com/t/exothermic-reaction/627920>\
**Category:** Factual Questions\
**Created:** [July 11, 2012, 7:13pm UTC](https://boards.straightdope.com/t/exothermic-reaction/627920 "2012-07-11T19:13:08Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![IceQube](https://avatars.discourse-cdn.com/v4/letter/i/dfb087/32.png) [@IceQube](https://boards.straightdope.com/u/IceQube)\
**Post date:** [July 11, 2012, 7:13pm UTC](https://boards.straightdope.com/t/exothermic-reaction/627920/1 "2012-07-11T19:13:08Z")

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I poured some bleach on a rag and started scrubbing.

The rag got really hot after 30 seconds.

Just to make sure it wasn’t the friction between the rag and the toilet seat, I took the rag, set it on the counter, and poured bleach on one part of it.

Sure enough, the part I poured bleach on was hot to the touch, unlike the rest of the rag.

The rag was part of a pair of old jeans.

Is there something in jeans that reacts with bleach?

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**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\
**Post date:** [July 11, 2012, 8:28pm UTC](https://boards.straightdope.com/t/exothermic-reaction/627920/2 "2012-07-11T20:28:19Z")

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Cotton?

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**Author:** ![Pasta](https://avatars.discourse-cdn.com/v4/letter/p/ecccb3/32.png) [@Pasta](https://boards.straightdope.com/u/Pasta)\
**Post date:** [July 11, 2012, 8:33pm UTC](https://boards.straightdope.com/t/exothermic-reaction/627920/3 "2012-07-11T20:33:53Z")

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> [@IceQube](#):
>
> Is there something in jeans that reacts with bleach?

Pretty much everything. Bleach is a strong oxidizer.

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**Author:** ![njtt](https://avatars.discourse-cdn.com/v4/letter/n/ecd19e/32.png) [@njtt](https://boards.straightdope.com/u/njtt)\
**Post date:** [July 11, 2012, 8:33pm UTC](https://boards.straightdope.com/t/exothermic-reaction/627920/4 "2012-07-11T20:33:54Z")

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More likely the blue dye. The whole point of bleach is to turn colored chemicals into colorless or white chemicals, and when it works, that is a chemical reaction, and it may be exothermic.

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**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\
**Post date:** [July 11, 2012, 8:47pm UTC](https://boards.straightdope.com/t/exothermic-reaction/627920/5 "2012-07-11T20:47:18Z")

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when you use bleach to bleach something whiter, you use it in a diluted manner (from the already diluted concentration in the bottle).

there was a fashion, to severely spot fade jeans, with a more concentrated amount of bleach. if someone did this with too concentrated amount and/or for too long then they would have a hole in the fabric where the bleach oxidizes the fibers to death.

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**Author:** ![rjk](https://avatars.discourse-cdn.com/v4/letter/r/ed655f/32.png) [@rjk](https://boards.straightdope.com/u/rjk)\
**Post date:** [July 11, 2012, 10:58pm UTC](https://boards.straightdope.com/t/exothermic-reaction/627920/6 "2012-07-11T22:58:07Z")

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Bleach works fast on jeans. I dribbled a bit of fairly strong bleach water on one leg of a pair of jeans, and went inside immediately to wash them, but it left a very prominent streak.

I thought maybe I should do some more on that one leg, washing often between applications, and see if I could start a fashion for one-leg spot-faded jeans. Is anybody with me?