Sciencemadness Discussion Board

Nitrous Oxide Acidity?

redox - 6-3-2011 at 11:23

I was reading an old chemistry book from the seventies that said oxides of nonmetals dissolved in water are acidic, e.g. : CO2, SO2, NO2, SiO2, P4O10, OCl2, etc. Nitrous oxide (N2O) immediately crossed my mind. It cannot be very acidic, as it is used as an anesthetic.
So my questions to you all are:

1. Is nitrous oxide acidic?
2. If so, what is the acid it forms?
3. If no, why is it not acidic?

Also, what about carbon monoxide and nitrogen monoxide?

Thanks!

Mixell - 6-3-2011 at 11:54

N2O is not acidic, it can be formed by the dehydration of hypo-nitrous acid (H2N2O2), but hypo-nitrous acid cannot be formed by dissolving N2O in water, also, N2O barely dissolves in water (0.15g/100ml at 15C according to wikipedia).
And about carbon monoxide and nitrogen dioxide I'm not sure, but I presume that they also do not generate acids on contact with water (Co is practically insoluble in water, even to a lesser extent than N2O).

redox - 6-3-2011 at 12:09

I once read nitrous oxide was actually quite soluble in water (I believe this is also why it is absorbed into the body so readily--it is soluble in human blood).

Mixell - 6-3-2011 at 12:15

Well, blood and water aren't the same things, but wikipedia may be bullsh**ing us, so we need a more credible source.

smuv - 6-3-2011 at 14:28

Nitrous oxide is not soluble in water, it is soluble in fats. This is makes it good both for making whipped cream and acting as an anesthetic.

ScienceSquirrel - 7-3-2011 at 03:49

Quote: Originally posted by Mixell  
N2O is not acidic, it can be formed by the dehydration of hypo-nitrous acid (H2N2O2), but hypo-nitrous acid cannot be formed by dissolving N2O in water, also, N2O barely dissolves in water (0.15g/100ml at 15C according to wikipedia).
And about carbon monoxide and nitrogen dioxide I'm not sure, but I presume that they also do not generate acids on contact with water (Co is practically insoluble in water, even to a lesser extent than N2O).


Carbon monoxide is the anhydride of the simplest organic acid, formic aka methanoic acid. It does not form the acid on contact with water but fused sodium hydroxide, etc will react to produce formates. Reaction of formic acid with sulphuric acid dehydrates formic acid to carbon monoxide.

White Yeti - 4-8-2011 at 07:18

Nitrogen monoxide forms nitrous acid when it dissolves in oxygen rich water. Nitrogen monoxide definitely follows the rule.

Mixell - 4-8-2011 at 07:44

Quote: Originally posted by ScienceSquirrel  
Quote: Originally posted by Mixell  
N2O is not acidic, it can be formed by the dehydration of hypo-nitrous acid (H2N2O2), but hypo-nitrous acid cannot be formed by dissolving N2O in water, also, N2O barely dissolves in water (0.15g/100ml at 15C according to wikipedia).
And about carbon monoxide and nitrogen dioxide I'm not sure, but I presume that they also do not generate acids on contact with water (Co is practically insoluble in water, even to a lesser extent than N2O).


Carbon monoxide is the anhydride of the simplest organic acid, formic aka methanoic acid. It does not form the acid on contact with water but fused sodium hydroxide, etc will react to produce formates. Reaction of formic acid with sulphuric acid dehydrates formic acid to carbon monoxide.

Actually, the real formic anhydride is C2H2O3.

ScienceSquirrel - 4-8-2011 at 09:13

Quote: Originally posted by Mixell  

Actually, the real formic anhydride is C2H2O3.



Do you think so?

AndersHoveland - 4-8-2011 at 09:27

Nitrogen dioxide is certainly acidic in solutions of water:
(2)NO2 + H2O <==> HNO3 + HNO2

But nitrous oxide seems relatively inert (at normal temperatures), perhaps because of the strong nitrogen-nitrogen triple bond, and the stabilizing resonance.

Mixell - 4-8-2011 at 10:10

Quote: Originally posted by ScienceSquirrel  
Quote: Originally posted by Mixell  

Actually, the real formic anhydride is C2H2O3.



Do you think so?

Well, I do, doesn't it create formic acid on contact with water?
CO is the dehydration product of formic acid, but it is not reversible.

ThatchemistKid - 4-8-2011 at 17:53

Well, Ill be damned I was going to say that formic anhydride has not been isolated in the form you just described up there outside of low temperature solutions of Diethyl Ether but apparently it recently has been isolated.

A quick search on google shows that C2H2O3 has been detected in the gas phase and isolated as a liquid but that it decomposes upon heating a bit above room temperature.

ScienceSquirrel - 5-8-2011 at 04:22

It really depends on how you view carbon monoxide and formic acid.
Formic acid is a carboxylic acid and could be viewed as organic so formic anhydride is the corresponding anhydride.
However it spontaneously decomposes to form water and carbon monoxide in strong solutions at room temperature and more rapidly when heated or treated with a strong dehydrating acid like sulphuric acid.
An anhydride does not have to react with water to form the acid, nitrous oxide is formed by the dehydration of hyponitrous acid but it will not react with water to reform the acid.

Mixell - 5-8-2011 at 06:23

Well, according to wiki:
"An acidic oxide (sometimes known as an acidic anhydride, but not to be confused with an acid anhydride) is an oxide that either
reacts with water to form an acid; or
reacts with a base to form a salt."

So both carbon monoxide and C2H2O3 can be regarded as "formic anhydride".
You know if nitrous oxide reacts to form salts with bases?

kryss - 6-8-2011 at 15:08

NO2 Acidic
NO Acidic ?
N2O Neutral.

IrC - 6-8-2011 at 17:40

Quote: Originally posted by smuv  
Nitrous oxide is not soluble in water, it is soluble in fats. This is makes it good both for making whipped cream and acting as an anesthetic.


Thus ending my lifelong quest to answer the question. Why after one day in the fridge did my low fat pie topper look like white runny diarrhea.