sodium (bad) + chlorine (bad) = salt (good)?

Somebody once gave me this example of an emergent property: the characteristics of sodium and chlorine separately are such that they are bad for you consumed in raw form, but when consumed as salt they are essential. Is this right? If I swallowed the amount of pure chlorine that I consume each day in the form of salt (or each week), would it harm me? :dubious:

Same quest for sodium.


Well, sodium would straightaway form sodium hydroxide with the water in your mouth tissues, grabbing all it needed from the cells if there wasn’t enough free water no matter what the cells felt about it, and then the sodium hydroxide would make soap out of the fat in your fat cells and penetrate quite deep in doing so. Chlorine - well, that’s quite corrosive too. I wouldn’t chance it.

I guess dissolved sodium ions and chloride ions don’t behave quite the same way as the pure elements… :slight_smile:

The raw forms of sodium and chlorine are Na(s) (the pure elemental metal) and Cl2(g) (the diatomic chlorine gas, Cl’s elemental form). In table salt, NaCl, we have Na+, the sodium cation, and Cl-, the chloride anion. You’re really looking at 4 different things, not 2 things in 2 different situations. I don’t know if this counts as emergent. If this does, everything in chemistry (and probably physics & bio, too) is emergent.

Sodium metal and chlorine gas both have deleterious effect on the body in any quantity if you consume them. Don’t. You might die, or hurt yourself. Salt is obviously ok in the short term, despite long term health problems.

Which means that, if there’s just one single molecule of Na in your saltshaker that has separated from its Cl, you’ll die and possibly explode.

Saltmaking is one of the most high-risk professions in the world.

Sodium will burn when it comes into contact with water. It’s a very energetic reaction, eating a 1/2 teaspoon of powdered sodium will burn the hell out of your mouth, throat and stomach. Clearly you could eat a teaspoon of salt without a trip to the ER.

Chlorine gas was used as a poison gas during WWI, I think that says it all WRT how safe it would be to consume.

Sodium and water

Poison gas in WWI

I know you’re being funny, but as a former chemistry teacher, I feel the need to fight ignorance where I see it.

As has been noted, there is a world of difference between elemental metallic sodium and sodium ion, and for elemental chlorine gas and chloride ion.

If you drop sodium chloride (NaCl) into water, the sodium ions will readily separate from the chloride ions. No danger whatsoever. They’re all still in ionic form, but now surrounded by water molecules.

In sold salt form they’re also in ionic form.

It’s not thermodynamically possible for the sodium ions present in sodium chloride to spontaneously revert back to elemental sodium. You many as well worry about all the air molecules in a room packing themselves into one corner of the room and causing you to suffocate.

Stop that! (or at least use a winky!)

Funny joke (I laughed) and all. But, someone unfamiliar with the basic chemistry might just get confused.

The OP has pretty well been answered, I think.

Bricks can be thrown. Mortar can be slathered onto something. Put them together to make a wall, and you have something which can neither be thrown nor slathered, but can do things that loose bricks and separate mortar cannot (e.g. be leaned against). Sketchy analogy, I know, but the point is that when certain things are combined in certain ways, they can lose their former properties and acquire new ones.

Think about the properties of pure hydrogen. Think about the properties of pure oxygen. Now think about the properties of water. (Also consider the difficulty of separating said water into pure hydrogen and pure oxygen.)

Elemental atoms have certain properties. Often among these is the tendency/ability to form certain compounds. Once the compound is formed, the former properties of the constituent atoms are changed. For example, the Na in a NaCl molecule is not going to bond with a Cl atom that happens along - it can’t, because the structure that could do that is already doing that, and is not available anymore. Nor is it going to react with water the way pure Na does. It is not its former self while incorporated in a compound.

A compound is a whole different animal from its discrete building blocks.

Great! Now I’m going to be dashing into the corners and waving my arms about frantically all day.

Actually, I really just wanted to post to nitpick something that Jake4 posted. As I’m quite sure he’s aware, salt (or at least the NaCl variety) is not just a good idea for short term, nor are there long term negative side effects. A lack of sodium-chloride is ultimately fatal in humans. All of the negative effects of salt are associated with overdoses.

Well, maybe. There’s salt added to a lot of pre-packaged and processed foods, so a good chunk of the population in developed countries don’t really have to worry about their salt intake. But obviously if most of what you eat you prepare yourself, then yeah, it’s a good idea to make sure every now and then to get some salt. Table salt is good to sprinkle on food every once in a while too for everybody because of the added iodine.

Now I just realized that you never said one had to add salt to anything, just that it is needed, so my last post wasn’t really needed.

Holy cow! Now you’ve given me something to worry about. I’ll never go without my oxygen tank and mask again! Knowledge isn’t power, it’s freaking scary!