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Are H+ and OH- ions always Aqueous?

as above.

I would assume they would be too reactive to exist in any other form, seeing as they come from acids and salts respecitively.

Reply 2

Liam 09

Yeah, they only exist in aqueous form, at A-level at least :P

Reply 3

perrytheplatypus

Original post by Liam 09

Yeah, they only exist in aqueous form, at A-level at least :P

What if they're molten?

Reply 4

nexttime

Original post by Liam 09

Yeah, they only exist in aqueous form, at A-level at least :P

Mass spectrometer is A-level isn't it?

Reply 5

yaya1

In AQA chemistry Mass spectrometer is there.
Thanks for the replies. :biggrin:

Reply 6

gingerbreadman85

Original post by gozatron

I would assume they would be too reactive to exist in any other form, seeing as they come from acids and salts respecitively.

Hydroxides are ionic compounds, acids are covalent ones. Thus molten hydroxides with OH^- should be possible, whereas H⁺ should only exist in solution (not just with water though, there are other solvents too).

Reply 7

Plato's Trousers

No.

H⁺ and OH^- are ions. They can exist in the solid, liquid and gas phases.

But if you are working at A level, then you are most likely to meet them in the aqueous phase, yes.

Reply 8

nexttime

Original post by gingerbreadman85

Putting this theory aside, ever heard of ionizing radiation?

Reply 9

Doughboy

Mass Spec is A-Level.

Reply 10

CitizensUnited

A general rule of thumb would be: if it has a charge, it is aqueous. (A-level knowledge)

Reply 11

gingerbreadman85

Original post by nexttime

Putting this theory aside, ever heard of ionizing radiation?

Sarcastic much?

I had my inorganic chem hat on, rather than my physical one, as i thought it was more relevant to the OPs question. Technically H⁺ doesn't exist in solution anyway, protonating a water molecule (or the solvent molecule) instead to give H₃O⁺

Assuming sufficient energy is supplied to a molecule, as in mass spectrometry, bonds can be broken (heterolytic bond fission) to form (generally) unstable and highly reactive gaseous ionic species (this is one reason why mass spec is done in a vacuum). OH^- is possible in negative ionisation mass spec (generally in A-level you only learn positive ionisation mass spec in detail) and H⁺ isn't generally detected on its own (not in the common ions table, though atomic hydrogen is), though it is found attached to things ([M+H]⁺, but this obviously isn't a free proton). Thus these ions are unlikely to be encountered in A-level Mass Spec.

If you fire enough EM radiation at them, or bombard them with enough charged particles they will "exist" until they react with something, which will generally happen pretty quickly. A naturally found example is the ionosphere, which is part of the upper layer of the atmosphere, where high energy radiation from the sun ionises whatever molecules migrate that far up. Generally A-level atmosphere chemistry focuses more on radical species (generated by homolytic bond fission) rather than ionic ones (at least the spec I know).

Protons (i.e. H⁺) are often used in physics. the LHC at CERN smashes together accelerated proton beams. This is firmly in the grounds of Physics though, so not sure that is relevant to the OP's original question.

As i mentioned, a molten ionic compound contains free ions (it conducts electricity so has to), so molten NaOH would have "free" OH^- ions. H⁺ doesn't exist in ionic species (H^- does in metal hydrides) so the only way to get it is to dissolve acidic species (short of high energy excitation of molecules). Water is not the only solvent capable of dissolving ionic compounds or dissociating acidic species so not all solutions will be aqueous.

(edited 13 years ago)

Reply 12

HannieTheConqueror

No, but in the context of acids and bases - yes.

Reply 13

charco

Study Forum Helper

In 1807 Sir Humphry Davy first isolated sodium metal by direct electrolysis of NaOH. This is pretty conclusive evidence to support the existence of free hydroxide ions.
http://www.periodic-table.org.uk/element-sodium.htm

(edited 13 years ago)

Reply 14

nexttime