Oxygen-based bleach

I remember the chlorine free liquid bleach era, but it was a couple of decades ago IIRC. Lasted about 3 months before the supermarkets realised that storing hydrogen peroxide was risky for them and the customer. The slightest contamination can cause it to swell in the container and explode. The last lot I bought came with a ventilated cap to allow the oxygen to escape.

You can still get laundry bleach (sodium percarbonate), which is a powder that releases oxygen when mixed with water.

Strange that it's only risky in Britain. Supermarkets in other countries in europe seem to cope perfectly well.

Yes, I buy "Ace" peroxide bleach in Italy. I get this rather than chlorine based bleach because it's better for use with our septic tank.

I trust you don't try to bring much of it back into the country, especially if you have a dark complexion and a beard!

(The 7/7 bomb ingredients included hydrogen peroxide)

Which is probably the real reason for it disappearing from retail stores, not some silly concerns about the health of elves.

Not silly at all. Not only can it swell in the container, it's also very handy for starting fires if you leave a rag soaked in it lying around.

Add chupatti flour and hit with a hammer...

Tell someone who's more ignorant than I.

The stuff found in retail stores for use a general bleach isn't going to be strong H202, less than 5% is more like it.

Many moons ago I foolishly poured some into a bottle after using it to bleach some wood. I don't remember the strength but it was sufficiently well diluted not to sting your hands too much. A couple of days later it blew the cap off with enough force to make a serious dent in the plaster ceiling (which I still haven't repaired), and that was due to very slight traces of caustic soda on the brush I'd been using. AIUI (and I may be wrong here) the dangerous thing about it is that

Right... so I won't find 6% hydrogen peroxide in chemists then. Oh, hang on. And I definitely won't find it in hairdressers. Oh, hang on. And I won't find it in the "bleach" section of every supermarket in Italy. Oh, hang on.

Here's a weeny, tiny, suggestion. The concentration is important as well as the chemical compound concerned. You can't make a bomb with 6% peroxide, you can't cause a rag to burst into flames witn 6% peroxide nor any of the other hand-wavy scaring s**te that is being mooted as possible.

To make a bomb, the bombers had to concentrate the H2O2 before it was suitable.

The example you give of returning used H2O2 to a sealed container simply shows that some people should not be permitted to use anything more dangerous than a rubber hammer.

U Sussex? Got an hour or two to spare?

Wander down to your chemistry department and ask the black-clad prodigiously-swearing postgrad clutching the crap roll-up and dreaming of firearms. He can tell you more than you ever wished to know on the topic...

(this probably works for most unis that still have a chemistry department).

Perhaps if you stopped asking questions, I'd stop answering them. Your replies beg a response.

Since kids no longer seem to actually _do_ chemistry at school, do undergrads get to do any at university?

Questions and constructive responses are the life blood of a newsgroup, but telling me I'm an asshole when I've already volunteered that information doesn't quite fit the bill. Anyway, I believe the official view now is that, once decanted from its original container, anything above 3% should not be returned to it (or to any other closed container), and I doubt whether most domestic consumers would instinctively know that, or bother to read instructions to that effect. I may well pour some out to do my streaks, realise that I have less hair than I thought, and not want to waste the excess. The

Perhaps you can point to the post in which I called you an "asshole"?

"some people should not be permitted to use anything more dangerous than a rubber hammer."

Read the label. All of the ones that I have seen explicitly warn customers to throw away excess and to dilute with plenty of water when doing so.

RTFL. I have read it. It says nothing of the kind.

They do at Sussex. "Number 1 chemistry department in the UK (the Guardian University Guide, 2008)." according to their website.

Owain

Problem would be finding someone.