I’ve picked up my Mom’s habit of aesthetic cleaning: monthly diluted-bleach soaks for the bottom of my stainless-steel sink and tea mugs to make them all pretty again. I’ll also do it to tupperware that’s been stained that gross orange by tomato sauces etc.
That got me wondering, though…how does bleach remove colour from all these different things? So far it’s worked on rust, tea, tomato sauce, chocolate, and burned stuff. When I was a kid, I thought of bleach working on clothes, and just assumed it dissolved dye or something. But that can’t be all it does!
So, help me out! My baseline is at a university-intro-level chemistry level, if that helps.
The active ingredient in regular bleach is Sodium Hypochlorite, which is an oxidising agent. Most dyes are chromophores and the bleach will react with them, breaking the, er, chromo bit.
bleach is not just a cleaner, like soap/detergent, it is an attacker. it does it’s job of bleaching or disinfecting by destroying. bleach is a good thing id used correctly; for example 8 drops in a gallon can purify water for drinking.
bleach is used diluted and is a mild hazard; if you mix with some other chemicals often used in cleaning it can form a poisonous gas. if you poured it out of the bottle (usually about 5% concentration in the USA) onto some fabrics then it might eat a hole through them.
some things might deteriorate faster if bleach, even diluted, is used on them.
some stains in Tupperware happen because the oils in the food get into the plastic, not just a stain on the surface that might happen with other food containers. that is why stains can be so hard to remove. the best is prevention is not to let the food be in there for a long time. oily foods might be placed in glass containers which don’t stain this way.
I think some molecules are colored because of their structure and electron energy levels. If you mess up their structure, the energy levels change and they lose their color/the color changes. This is how colors fade. I think it’s also one of the ways bleach works.
This agrees (approximately) with what I learned in college Chem-1 – but it left me wondering: Why is the color change permanent? Why don’t the colors return after the bleach is rinsed out? Clearly, there must be some reaction with the pigment molecules, leaving you (permanently) with different molecules than where there before.
some molecules have a color because they absorb the other colors, this would be in a molecule like a dye. UV light can break molecules up especially over the long term. the large dye molecules being damaged leads to permanent fading.
Because you’re permanently destroying the molecules that provide the color. Oxidizing reagents like bleach are desperate for electrons and will rip them off anything they can find, leaving tattered remains of quietly whimpering molecules in their wake.
Right—when your electronegativity is 3.2, you can make anybody your bitch (except fluorine). I think I got that right—too lazy to look it up. And I probably misspelled ‘fluorine’; I always do.