What are the common items that should have a smell?

January 13, 2023 10:50 AM

I mean, common "household" items. Bleach, hydrogn peroxide, what else should not smell like nothing or good for safety reasons, and just so no fraud can take place, (i.e no one can replace the content with water).
posted by amfgf to Science & Nature (15 answers total)

I'm not answering the question, just adding.
When I say water I mean the ones that don't come flavoured, and some city water that don't smell like chlorine.
posted by amfgf at 10:56 AM on January 13, 2023

Gas is the only one I can think of. Your examples are not really 'things that should not smell like nothing for safety reasons' - they just happen to have specific smells. Gas has an additive to make it detectable when there's a leak.
posted by pipeski at 11:09 AM on January 13, 2023

popeski,
Do you mean it's ok, if the bleach or hydrogen persoxide you bought has no smell to them? Would you not retturn them?
posted by amfgf at 11:29 AM on January 13, 2023

Not popeski but work in science... Hydrogen peroxide (at least at the percentages you buy at the drug store for cuts and scrapes) really doesn't have a smell at all. Bleach will smell like...well....bleach. Assuming normal household chlorine bleach it should smell a bit like chlorine (swimming pool smell). Other than natural gas nothing really has added smells for safety, at most they may use color dyes or in rare cases bitterants to keep people from wanting to ingest them.

Can you smell other things? When I had COVID I completely lost my sense for smell for a good two weeks....it made dinner time very boring.
posted by Captain_Science at 11:35 AM on January 13, 2023

Bleach decomposes into salt water at a rate of about 20% per year. If it's been on the store shelf for several years then it wouldn't have much smell (or bleach) left, and yeah, I might return it for being expired. That's pretty unlikely, though.
posted by jedicus at 11:58 AM on January 13, 2023

Isopropyl alcohol, methylated spirits, acetone (often used in nail polish remover), naphtha and turpentine are all colorless fluids that might be mistaken for water at first glance, and all have quite distinct smells. The smells are not added for safety or anti-fraud reasons, those chemicals just smell like that.

Methylated spirits is mostly ethanol, but also has other alcohols and ketones added to it to make it less safe to ingest. And on top of those it also has a powerful bittering agent added to make it so that only truly desperate people will ignore the widely understood fact that meths has been deliberately made poisonous.

Kerosene is usually dyed blue, and gasoline yellow or green or pink depending on the grade. Again, each of these has its own characteristic smell and again, that's not been added.
posted by flabdablet at 12:09 PM on January 13, 2023

Ammonia has a very distinct smell
Windex/window cleaner
Vinegar

Most cleaning products have their own scent - whether added or natural or a combination of both.
posted by hydra77 at 12:27 PM on January 13, 2023

Vanilla and other baking extracts. Essential oils. Insect sprays.
posted by Iris Gambol at 1:33 PM on January 13, 2023

what else should not smell like nothing or good for safety reasons, and just so no fraud can take place, (i.e no one can replace the content with water)

If a liquid or substance that doesn't have a natural smell has some kind of scent added, it's totally for safety reasons, not as some kind of anti-fraud measure.

Do you mean it's ok, if the bleach or hydrogen persoxide you bought has no smell to them? Would you not retturn them?

I might well be jumping to conclusions, but if you're asking these questions because you've just gotten something that has no smell when it should, my first thought would not be "my bleach has been swapped for water" but "I might have COVID." Losing your sense of smell is one of the common symptoms. You should test.
posted by soundguy99 at 3:35 PM on January 13, 2023

Rubbing alcohol and vodka?
posted by Vatnesine at 4:15 PM on January 13, 2023

All I know is every hydrogen peroxide I bought/used has had a distinct smell. So, if there is one that doesn't have a scent, I'm not buying/using. I mean why woukd the smell be removed? What about the blind/sight impaired?
posted by amfgf at 5:41 PM on January 13, 2023

Thanks to all. I'm pretty sure it's not COVID, since it's just one item.
posted by amfgf at 7:39 PM on January 13, 2023

When hydrogen peroxide breaks down, which it will certainly do over time while in storage, it does so into water and oxygen: 2H₂O₂ → 2H₂O + O₂. And since air is already 20% oxygen, if you're smelling anything at all coming out of a bottle of typical home-grade 3% peroxide solution right after unscrewing the cap then it's more likely to be the scent of the bottle itself, perhaps a plasticizer in the bottle walls or the glue from the cap seal, than the actual breakdown oxygen.

Pouring a little peroxide onto a bit of fresh cut raw potato will give you a much more reliable idea of how active it still is than trying to detect it with your nose. If it's still good, it will fizz.

The bubbles in that fizz, by the way, are made of the pure oxygen generated by the rapid breakdown of peroxide. Pure oxygen is itself a very reactive substance and toxic to most microbes, which is why peroxide works as an antiseptic and also why it feels like it's burning you if you pour it on a cut: it literally is.
posted by flabdablet at 9:55 PM on January 13, 2023

Household 3% peroxide does have a smell, to me, or maybe it has a feeling in the nose. But this does not seem to be a consistent perception -- there may be individual differences or the perception might be of oxidized impurities.

tl,dr a bubble check is more reliable than a nose check.

A chemist's review of peroxide odor:

So far I have been unable to find a reference that gives an odor threshold for hydrogen peroxide. Some references say that hydrogen peroxide has no odor, others that it has a slightly sharp odor, or sharp odor and bitter taste.
[...]
most people seem to agree that at low concentration there is no odor, at 3%, 6% and even up to 30%, though others report a slightly acid odor at this concentration. Personally, I smelt nothing from bottles of either 3% or 30% solution.
[...]
In some applications such as when using sterilizers there is an odor that people sometimes associate with hydrogen peroxide. As far as I know no studies have been performed to identify the origin of this odor, and it is probably the result of partially oxidized volatile organic compounds

posted by away for regrooving at 10:17 AM on January 14, 2023

Thank you all for answering. Thank you flabdablet! The potatoe test worked.
posted by amfgf at 1:45 PM on January 21, 2023