Making Acids

[frosch45]

If I had a crystal or a gas of another element and I had hydrogen gas, how could I combine these two to make an acid? Any ideas? Or is there another process...

[CaptainPanic]

In a very, very general way, an acid is a combination of any compound and hydrogen where the hydrogen can come off as a proton when it is dissolved in water.

 

My guess is that your best way to make an acid is to look up a number of synthesis routes, and study those. Some strong acids are: H2SO4, HNO3, HCl. These all come from gases (see: wikipedia for synthesis).

 

Of those 3, only HCl needs hydrogen in its production:

H2 + Cl2 --> 2 HCl (don't try this at home if you're no expert)

 

I have never heard of an organic acid that needs hydrogen in its synthesis. Organic acids are very oxidized (they contain a relatively large amount of oxygen atoms), and hydrogen will actually reduce them.

Like: Formic acid + hydrogen --> methanol + water

HCOOH + 2H2 --> CH4O + H2O

 

Acids from crystals... Any crystal with NH4 in it is already an acid, so that's not what you meant. Eeeh... Ok, sorry, no suggestions at the moment.

 

I just realize that all acids I mentioned can be made from minerals as well. (Sulfuric acid is the acid form of a sulphate, and sulphate is a compound in minerals). Still, you don't need hydrogen (not in its gaseous form at least) to make the acids.

[thedarkshade]

Reacting directly with hydrogen does not give directly an acid. First there is formed the anhydride. By reacting directly with Br and H you get HBr but it turns into and acid only when dissolved in water. And reacting directly with hydrogen usually requires catalysts and specific temperatures.

 

From crystals? Acidic oxides in reaction with water give acids.

[dom3mo]

So would bubbling chlorine through hydrogen peroxide make Hydrochloric acid?

[thedarkshade]

So would bubbling chlorine through hydrogen peroxide make Hydrochloric acid?

Only after dissolved in water!

[chemkid]

Well if we are bubbling through aqueous (of course) hydrogen peroxide the acid would immediately be dissolve (right?)

 

Chemkid

[NATT]

Hell.. looks like some kinda interesting point. Bos, as mr.chemkid said, Can we make HCl By bubbling Cl2 through H2O2????

[Theophrastus]

In terms of simply bringing together hydrogen gas (H2) and chlorine, iodine or bromine (Cl2, I2, Br) the problem is that the diatomic gases have little reason initially to interact with one another under ordinary conditions, unless you are to increase the temperature, use a catalyst, or something else of the like. But yes, the method remains valid, after which you could then bubble the anhydrous gas through water, where the dissociation results in the production of acid.

 

In terms of the hydrochloric acid, it's far easier to simply buy 30% hydrochloric acid, sold as muriatic acid, from a hardware store, which is both easy and cheap.

 

In regards to chemkid's idea, to produce [ce] HCl [/ce] the method is invalid, as due to the instability of the oxygen to oxygen bond in hydrogen peroxide, the reaction, will not produce hydrochloric acid and diatomic oxygen, but instead, will initially produce hypochlorous acid, a weaker acid, but a much stronger oxidiser, and is far more corrosive and dangerous. In contact with acids, it generates chlorine gas. (which of course extraordinarily poisonous)

 

[ce] H2O2 + Cl2 -> 2HClO [/ce]

 

[ce] 2HClO + 2H+ -> H2O + Cl2 [/ce]

 

If you intend to make hypochlorous acid, you should once again use purely glass apparatus, for its containment, and keep it in tinted glass or in an opaque container, in a cool dark area, as light and heat, result in it decomposing to hydrochloric acid.

 

[ce] 2HClO -> O2 + 2HCl [/ce]

 

However, as a means to obtain hydrochloric acid, (decomposing [ce] HClO [/ce]) it is not good, as your product, shall be tainted with hypochlorous acid impurities, and the decomposition process, if coerced by heat, may become very violent.

 

In regards to the other query of Sulfuric acid, the only viable home synthesis method I know of, is to bubble sulfur dioxide gas, into hydrogen peroxide, which you can buy from suppliers at a (relatively) concentrated 30%.

 

[ce] SO2 + H2O2 -> H2SO4 [/ce]

 

However, you should note that sulfur dioxide is vastly poisonous, and you should test any apparatus for leaks, before performing the reaction.

 

If possible, it is simpler to just buy sulfuric acid outright. Some hardware stores and the like, sell it, under various names. If you already have sulfuric acid, you can easily make [ce] HCl [/ce], if you wish, simply by reacting the sulfuric acid, with table salt, as so:

 

[ce] H2SO4 + 2NaCl -> Na2SO4 + 2HCl [/ce]

 

The final strong acid, nitric acid, I do not recommend making, unless you have the practical expertise, and the necessary apparatus to undertake the reaction. It is not a complex process, but a dangerous one, due to the release of deadly [ce] NO2 [/ce]. You should use full glass apparatus, as [ce] NO2 [/ce], attacks most rubber and plastics, sealing any leaks, or possible holes with teflon tape. In storing it, as it does over time produce deadly [ce] NO2 [/ce] gas, due to decomposition of the acid, store it in a cool place, in a container of dark tinted glass, as exposure to light can bring about increased decomposition.

The process itself, involves the funnelling of NO2 gas, into water. The [ce] NO2 [/ce] can be produced by heating a nitrate salt, resulting in a metal oxide, and red- brown [ce] NO2 [/ce] gas.

 

[ce] H2O + 3NO2 -> 2HNO3 + NO [/ce]

 

But again I stress that this is a rather dangerous method, and ought be performed with caution. Check the MSDS for all of these compounds, to understand any health hazards involved.

 

As for organic carboxylic acids, these can be rather simply formed, through the oxidation of primary alcohols, with strong oxidisers (As captain panic implied ) like [ce] KMnO4 [/ce] or [ce] K2Cr2O7 [/ce] (potassium permanganate, and potassium dichromate respectively)

 

[ce] RCH2OH + O2 -> RCOOH [/ce]

 

(here, R represents a non- functional group, which varies, depending upon the alcohol used (ie ethanol, butanol, phenol))

 

In terms of attaining the acids from minerals, while sulphate minerals exist, they can not be easily used to produced sulfuric acid, unless reacted with a more corrosive (not necessarily stronger) acid, such as nitric acid. In terms of minerals, salt is also known, as the mineral halite, but I don't really see what you're trying to get at with this.

 

(Whew, that was some hell of a long post )

Edited July 24, 2009 by Theophrastus

[monterto]

I have been trying to make HNO3 for a while now using NaNO3 and copper metal. I'm not sure about my method. I've been making CuNO3 and heating it and bubbling the gasses through distilled water. I chose the CuNO3 simply because the first time I made it, I saw that it decomposes pretty quickly when heated while testing some of its properties.

 

Advice?

 

I have all my high school chemistry credits and hoping to study in post secondary.

[hermanntrude]

if the answer is at all possible or feasible, it's in this thread.

 

guess how I found it

 

answer: (highlight this line to see it):use the search function!!!!

[Melvin]

Hmm...copper is below hydrogen in the activity series, right? Would hydrogen react with copper salts (like sulfate) to form the corresponding acid?

[UC]

Hmm...copper is below hydrogen in the activity series, right? Would hydrogen react with copper salts (like sulfate) to form the corresponding acid?

 

In theory yes, but it's worthless in practice as hydrogen reductions of metal compounds need to be carried out in furnaces to get them to work.

[Melvin]

Hmm...what about in aqueous solution? I suppose getting the hydrogen to react before it bubbles out would be difficult...

[frosch45]

Well, since joining the forum a couple of years ago, I've actually learned some chemistry. I look back on my questions and I chuckle a little on the inside because of what I asked.

 

I made an informative video a few months back about the synthesis of nitric acid. Take a peak and rate it!

 

 

I've learned a bit since I have joined.