Can anyone answer me this question about bleach

[Corky34]

Nothing's a bleach as bleach and/or bleaching is a process not a thing, there's nothing in the periodic table called bleach or for that matter sodium hypochlorite.

I'm not sure how i can be clearer.

[DDY]

Your semantic pedanticism is confusing, but I now understand your point.

Fine...

I shall call it a bleaching agent.

Or, you know what's a better term - bleach!

A verb can also be a noun!

[Corky34]

Well i, we, did start by saying technically

[ik9000]

FFS what do you call water? That's an accepted name of a mixture of chemicals - just as is bleach. Get over yourself.

[peterb]

Your semantic pedanticism is confusing, but I now understand your point.

Fine...

I shall call it a bleaching agent.

Or, you know what's a better term - bleach!

A verb can also be a noun!

Indeed, as I referred in an earlier post, bleaching is the action of discolouration, sunlight will bleach fabrics for example, so sunlight is a bleaching agent, but in common use, bleach referees to a chemical or something that causes an item to be be bleached!

Love this thread - from a simple question through to the action of acids and alkalis, into the semantics of the English language!

And all carried out in the spirit of education, enquiry and in a good natured way... well apart from this..

FFS what do you call water? That's an accepted name of a mixture of chemicals - just as is bleach. Get over yourself.

Which I will put down as a moment of aberration just after the poster tripped over the cat or similar. But I have tried to bleach it out.

Anyway I think corky' comment should be taken with a pinch of NaCl, but that is the end of my pouring mineral hydrocarbons on troubled H2O, so keep it friendly please.

[DanceswithUnix]

If your bog is properly minging - use a half a house brick! the brick is softer than the enamel on the throne, and way harder than ANYTHING that'll cling to it

Sounds a bit scary

I use a cleaning eraser. Not sure where I bought it, a DIY shop I think (think it was wickes or homebase but couldn't find a link just now). Basically it feels like a really harsh pencil eraser, but designed to work on enamel. Just rubs out the stains with minimal effort. Quite cheap too compared to the variety of chemicals that are normally used, specially handy for the bath.

[Zak33]

Nothing's a bleach as bleach and/or bleaching is a process not a thing, there's nothing in the periodic table called bleach or for that matter sodium hypochlorite.

I'm not sure how i can be clearer.

actually I think this is a perfect sentence.
he's right

To vacuum a living room carpet MEANS to use a Dyson or Hoover on it.. which uses a vacuum to clean it of dust.

but the phrase "to vacuum" is wrong.

to bleach a toilet of stains is correct..it's an action..... but to call the liquid "bleach" is like calling a sponge a "scrub" or a loaf of a bread "an eat"

great reply

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I am NOT using a flippin house brick Tumble. my loo is mint...

well...white.

A bleaching liquid purchased in a plastic bottle is a better definition.

[SeriousSam]

FFS what do you call water? That's an accepted name of a mixture of chemicals - just as is bleach. Get over yourself.

Universal solvent... corporation pop... the world is your mollusc as they say

[ik9000]

Go into a store and ask for bleach. They'll know exactly what you mean. We all do. Whether or not it might be better described by its chemical formula, we all know what bleach is. Same way we all know what we mean by "air", "water", "coca cola" and similar. Bleach is a noun, not just a verb, and accepted in the dictionary. Even just google one word - bleach - brings up the product rather than any spiel about "technically it's a process." Not to the everyday person it isn't. It's just an accepted name for a product, same as unleaded petrol, diesel or the rest. Those all vary in different countries, countys and have different mixes for the ambient climate at different times of year. None of us get our knickers in a twist as to whether we should be referring to them as octane-98 distillate, low sulphur with extra cracked volatility enhancers for winter conditions. We just call it petrol, or maybe unleaded petrol (though that's less an issue now you can't get 4star leaded). I give you bleach. Just bleach.

[DDY]

actually I think this is a perfect sentence.
he's right

To vacuum a living room carpet MEANS to use a Dyson or Hoover on it.. which uses a vacuum to clean it of dust.

but the phrase "to vacuum" is wrong.

to bleach a toilet of stains is correct..it's an action..... but to call the liquid "bleach" is like calling a sponge a "scrub" or a loaf of a bread "an eat"

great reply

----
I am NOT using a flippin house brick Tumble. my loo is mint...

well...white.

A bleaching liquid purchased in a plastic bottle is a better definition.

C'mon. Just because a word is a verb or a noun does not preclude it from also being the other.

It's like saying it's incorrect to call something an auction, bomb, cover, dam, film, guard, hammer, iron, jail, knot, land, mine, nest, oil, photograph, quiz, relay, shelter, track, uu...(umm), voice, wreck, x......yz. Because they're also action words, or verbs...

[Butcher]

Technically household bleach is an acid - by the definition that it has dissociated H+ ions and can donate protons. The active chemical you get in household bleach is a sodium salt (NaOCl), but in solution the important part is HOCl which is called hypochlorous acid for a reason!

Like I poorly explained above, HOCl is a weak acid, it doesn't dissociate much at typical tap water pH and even less at the alkaline pH that bleach is typically supplied.

So you're right and wrong. Right in the technical definition, but wrong because if you stick pH indicator in bleach, it will come up as alkaline.

This is mind bending stuff, acid, but alkaline at the same time? I don't get it either, but it's what I've memorised for my exams next week!

yes there's a name for that- chemicals that can act as acid or bases (alkalis) depending on the relative potentials of the chemicals they're mixed with. is it amphoteric? been a while since I looked at this stuff. ammonia is another one. in the presence of a strong acid it acts as a base, but mix with an alkali and it behaves as an acid.

Yes amphoteric is the correct term. It works because an acidity is the property of being able to donate a proton. While basicity is the property of being able to receive one. Some molecules have groups which can do each of these and so can act as both at once.
Note however that HOCl isn't amphoteric, nor is household bleach.

Bleach is alkaline because it's full of sodium hydroxide (NaOH) which is a strong base. HOCl is a weak acid, so is mostly present as undisassociated HOCl molecules rather than H+ and OCl- ions, as such the large number of OH- ions from the NaOH means the solution has a high pH.
Bleach works because some of the HOCl disassociates in solution. The H+ ions react with OH- ions to produce water leaving a OCl- ions - it is these that provide the active effect.

[ik9000]

Bleach is alkaline because it's full of sodium hydroxide (NaOH) which is a strong base. HOCl is a weak acid, so is mostly present as undisassociated HOCl molecules rather than H+ and OCl- ions, as such the large number of OH- ions from the NaOH means the solution has a high pH.
Bleach works because some of the HOCl disassociates in solution. The H+ ions react with OH- ions to produce water leaving a OCl- ions - it is these that provide the active effect.

So are you saying the OH- from the NaOH (solution) reacts with H+ from the HOCl (solution) leaving the Na+ to react then with OCl- and form a salt which remains dissolved in the water just created? Acid + Alkali = salt + water and all that.... I used to know all this stuff. Staring back into the mists... What are the reaction potentials and partition coefficients? Presumably there's a medley and the reaction can't fully complete?

[Butcher]

So are you saying the OH- from the NaOH (solution) reacts with H+ from the HOCl (solution) leaving the Na+ to react then with OCl- and form a salt which remains dissolved in the water just created? Acid + Alkali = salt + water and all that.... I used to know all this stuff. Staring back into the mists... What are the reaction potentials and partition coefficients? Presumably there's a medley and the reaction can't fully complete?

Not quite, the Na+ and OCl- wouldn't actually react, they would just stay dissolved, if you dried it out they would crystallise as NaOCl though.
The reason it doesn't all react is that as the concentration of OCl- increases, it becomes less thermodynamically favourable for the HOCl to disproportionate in H+ and OCl-. I couldn't tell you the reaction potentials and partition coefficients offhand, however HOCl has a pKa of 7.52 and thus would be largely undisassociated to start with, before other considerations.

There also a further reaction in bleach (which contains large amounts of NaCl): HOCl reacts with Cl- (from NaCl) and H+ ions to give water and chlorine. This is what gives bleach it's chlorine smell and why if you leave it too long it becomes less concentrated.

[ik9000]

Not quite, the Na+ and OCl- wouldn't actually react, they would just stay dissolved, if you dried it out they would crystallise as NaOCl though.
The reason it doesn't all react is that as the concentration of OCl- increases, it becomes less thermodynamically favourable for the HOCl to disproportionate in H+ and OCl-. I couldn't tell you the reaction potentials and partition coefficients offhand, however HOCl has a pKa of 7.52 and thus would be largely undisassociated to start with, before other considerations.

There also a further reaction in bleach (which contains large amounts of NaCl): HOCl reacts with Cl- (from NaCl) and H+ ions to give water and chlorine. This is what gives bleach it's chlorine smell and why if you leave it too long it becomes less concentrated.

but hang on, where are those H+ ions coming from? NaCl + HOCl -> NaOH(aq) +Cl2(g)? That doesn't sound right. Or you mean 2HOCl -> H2O + Cl2 + O2- (which then goes where? Peroxide, or does it give off oxygen too?)

[Butcher]

but hang on, where are those H+ ions coming from? NaCl + HOCl -> NaOH(aq) +Cl2(g)? That doesn't sound right. Or you mean 2HOCl -> H2O + Cl2 + O2- (which then goes where? Peroxide, or does it give off oxygen too?)

There are H+ ions from disassociated HOCl. It's a slow reaction as there aren't many H+ ions in an alkaline solution.
Effectively NaCl(aq) + 2HOCl(aq) <-> NaOCl(aq) + H2O(l) + Cl2(g).

It's also why mixing in acid is a bad idea since it provides a large amount of H+ ions and hence a large amount of chlorine gas.

[Tumble]

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I am NOT using a flippin house brick Tumble. my loo is mint...

well...white.

hehe wuss