# Are there any guidelines for what constitutes an “organic acid” regarding storage requirements?

I am moving a large amount of chemicals to a new lab and I’m curious about any guidelines for chemical separation. I’ve seen suggestions that organic acids and non-organic acid be stored separate from one another, and away from general chemicals. However, where would a long chain fatty acid lie, general chemical, or organic acid? When they get long enough, they become a solid at room temperature. Does storage requirements change for organic acids which are solid?

@Jan is correct.

Organic vs. inorganic is not the main concern for acid storage. The strength and oxidizing ability of the acids is a much more serious issue.

Your institution/company may already have internal safety guidelines that you should follow. If not, your country/province/state will have occupational health and safety regulations that you will need to respect.

You can find the American Chemical Society's safe storage guidelines here.

In general, I would not pay too much attention on the difference between organic acids and inorganic ones in principle. Rather, the deciding factor should be how strong the acid is (i.e. how bad things are if it is spilt or the bottle breaks) and whether or not it produces acidic fumes.

For a general rule, see if the acid has been rated corrosive. If so, store in a separate acid cabinet. This will include inorganic ones like hydrochloric or sulphuric acid but also organic ones like acetic acid. It will ignore weak inorganic acids and weak organic acids alike because they can easily be stored with the general chemicals.

$$\ce{HNO3}$$ and $$\ce{HClO4}$$ and their salts should be stored as far as possible from any organic compounds, because oxidizers should be stored away from reducers.

That said, some organic compounds might produce toxic compounds in strongly acidic or basic solutions. Formic acid, in particular, decomposes in concentrated sulfuric acid, producing toxic and flammable carbon monooxide.

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As for storage suggestion.

Concentrated volatile acids ($$\ce{HHal}$$, $$\ce{HNO3}$$, formic and acetic acids) will leak through most containers, causing rapid corrosion of the surroundings. Same for bromine, ammonia and to lesser extent for some organic solvents. Storing them in separate location with very good ventilation is common sense. Furthermore, many concentrated acids might produce toxic fumes on reaction with rather innocent salts. Mixing nitric acid and table salt without reason is not advised. Mixing strong acids with each other isn't advised either, because again toxic fumes might develop.

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In general, you should either ensure that any possible mix in the batch you move or store does not explode or produce large amount of toxic fumes (especially if they are not irritating) or take special cautions to ensure that the containers will not break even under high stress.