How come Nacl is not poisonous?

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Discussion Overview

The discussion centers around the question of why sodium chloride (NaCl) is not considered poisonous, despite its constituent elements, sodium (Na) and chlorine (Cl2), being toxic. Participants explore the differences in properties between elements and their compounds, particularly focusing on the chemical behavior and reactivity of ions versus their elemental forms.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants assert that compounds exhibit different properties than the individual elements they are composed of.
  • There is a discussion about the reactivity of sodium and chlorine, with sodium being highly reactive and chlorine existing as Cl2 in its elemental form.
  • One participant questions whether the small displacement of electrons during the formation of NaCl is responsible for the significant difference in properties compared to its constituent elements.
  • Another participant emphasizes that the chemistry of a substance is defined by its electron configuration, suggesting that changes in electron configuration lead to different reactivities.
  • Some participants mention the concept of dose in toxicology, arguing that anything can be poisonous at certain concentrations, including NaCl.
  • There is a technical explanation involving Coulomb's law and electric fields, discussing how small changes can lead to large effects in chemical properties.
  • One participant draws a parallel with oxygen, noting that while O2 is essential for life, O3 (ozone) is toxic, highlighting the complexity of chemical behavior.

Areas of Agreement / Disagreement

Participants express a range of views on the properties of NaCl compared to its elemental forms, with some agreeing on the differences in reactivity and toxicity, while others emphasize the role of concentration in determining toxicity. The discussion remains unresolved regarding the extent to which the small changes in electron configuration account for the differences in properties.

Contextual Notes

Participants mention various assumptions and principles, such as the dose-response relationship in toxicology and the implications of electron configuration changes, without reaching a consensus on these points.

Naveen345
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Na is poisonous for us, so is Cl2 (chlorine).
How come Nacl is not poisonous?
 
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Compounds have different properties than elements they are made from, period.
 
Naveen345 said:
Na is poisonous for us, so is Cl2 (chlorine).
How come Nacl is not poisonous?

Elements can be highly reactive- like sodium...It wants to give away one electron like crazy:
It will donate this electron to almost any other element. Now it is sodium+1, an ion.
A Chlorine atom is also reactive, but it wants an electron so badly that it usually shares one with another Chlorine atom and is found as Cl2. But this pair is still extremely reactive and will react with nearly any other atom to get more electrons: They then form 2 Chloride ions which are described as Cl single minus. These ions stay the same when dissolved in water, where the Na+ and Cl- disassociate from each other to make salt water. All animals need Na ions to make their bodies and nervous systems operate properly, also Potassium and Magnesium ions.
 
Borek said:
Compounds have different properties than elements they are made from, period.

When Nacl is formed electrons are displaced by a very very small distance and new bonds are formed? Is such a small change responsible for such huge difference in properties of the new compound?
 
Naveen345 said:
When Nacl is formed electrons are displaced by a very very small distance and new bonds are formed?

See explanation by dacarls.

Is such a small change responsible for such huge difference in properties of the new compound?

Yes.
 
naveen
When Nacl is formed electrons are displaced by a very very small distance and new bonds are formed? Is such a small change responsible for such huge difference in properties of the new compound?

dacarls explanation goes deeper than you might think, so take heed of Borek's advice.

When you ingest salt you are ingesting sodium and chloride ions. These have vastly different properties from the parent atoms or molecules of sodium or chlorine and are no longer bonded together.

So that small shift of an electron does indeed have huge consequences.

You may have heard of something similar but reversed with another substance.

Oxygen.

The normal molecule O2 is life giving but another form O3 (Ozone) is poisonous, except in very small quantities.

Worse, the ions from oxygen (there are several types) can cause cancer.

So it is the reverse since the molecule is beneficial and ion deadly in this case.
 
Naveen345 said:
When Nacl is formed electrons are displaced by a very very small distance and new bonds are formed? Is such a small change responsible for such huge difference in properties of the new compound?

The chemistry of a substance is essentially defined by its electron configuration. If you change the electron configuration, you completely change its reactivity with other substances.
 
2ufg8eh.jpg

The process of NaCl making is pretty much like that. Trust me, I saw it with a electroquantum microscope.

(No, I didn't.)

You can see how the chloride has one empty slot for another electron. It wants it so bad it decided to steal one from the first element in sight.
Dialogue balloon are that size because that image wasn't intended for English.

Borek said:
Compounds have different properties than elements they are made from, period.

^
 
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Ygggdrasil said:
The chemistry of a substance is essentially defined by its electron configuration. If you change the electron configuration, you completely change its reactivity with other substances.

well... carbon monoxide and nitrogen are isoelectronic. its a bit more subtle; vibrational spectra, which determine thermal stability, depend also on masses. also there's stuff like the isotope effect in superconductors.

all in all, its very messy but in general its correct =)
 
  • #10
chill_factor said:
well... carbon monoxide and nitrogen are isoelectronic. its a bit more subtle; vibrational spectra, which determine thermal stability, depend also on masses. also there's stuff like the isotope effect in superconductors.

all in all, its very messy but in general its correct =)

Very good point.
 
  • #11
Naveen345 said:
Is such a small change responsible for such huge difference in properties of the new compound?
The point is that although the electrons are only moved over small distances, the electric fields working are enormous. The reason is Coulombs law stating that the electric field seen by an electron near an ionic core depends on ##1/r^2## where r is the distance of the electron and the center of the ion. As r is a small quantity, the fields are huge.
 
  • #12
DrDu said:
The point is that although the electrons are only moved over small distances, the electric fields working are enormous. The reason is Coulombs law stating that the electric field seen by an electron near an ionic core depends on ##1/r^2## where r is the distance of the electron and the center of the ion. As r is a small quantity, the fields are huge.

Force are much more stronger in the nucleus. Does it mean displacing a proton by a very-very-very-very small distance will produce dramatic effects?

What about plank's scale. If sub atomic ( protons, quarks etc. ) particles move by only that much distance or even less distance than that? Will dramatic effects still occur? By dramatic I mean, a huge change in the erstwhile properties.
 
  • #13
naveen
Force are much more stronger in the nucleus.

Careful how you put this for you are implying that one zone of space is different from any other.

One of the most important underlying principles of all science is that primary laws are the same everywhere, ie in every zone of space.
 
  • #14
I love when people say something isn't poisonous, because how lacking science can be in terms of rigorous definitions is amusing to me.

One principle of toxicology is that the dose makes the poison. ANYTHING, in a certain concentration, can be said to be "poisonous." In fact, Wikipedia lists the median lethal dose between 3000 and 8000 mg/kg (for tested small rodents). This means that in a sample of small rodents, 50% of them will die when given sodium chloride in an amount between 3000 and 8000 milligrams for every kilogram of body mass.

It becomes more of a question of biology, but it can be fairly simple to see how a large amount of NaCl might affect a biological system (exempli gratia the human body):

Let's imagine, for simplicity, that the cytoplasm is an ideal solution. Cell membranes are semipermeable, so we can model the osmotic pressure using the equation \Pi = i MRT. Let's also assume that the LD50 of tested animals from Wikipedia translates decently well to humans. With a 70 kg person (and 8000 mg NaCl per kg body mass) and 5 liters of blood, we get a 1.916 M NaCl solution. Assuming an average internal body temperature of 310.15 K and NaCl to have a van't Hoff factor of 2, we get that the osmotic pressure is \Pi = iMRT ≈ (2)(1.916)(0.082)(310.15) ≈ 97.57 atm. This means that one needs to apply a pressure of 97.57 atm in order to negate osmosis. In essence, cells start to become drained of their internal fluids and begin losing functionality. In other words, death.
 
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