Acid - Liquid to Solid - Solid to Liquid - Conversion Table

What are the conversions for Liquid to Solid and Solid to Liquid amounts of the following acids:

Lactic
Citric
Phosphoric

In other words, if I need 1ml of citric how many grams of solid would that be, or if I need 1 gram of citric solid how many ml of liquid would that be. Of course it probably depends on the strength of the liquid acid solution.

I know some of the water spreadsheets have these types of conversions but I can't find it for citric which I have as a solid.

If this is even possible, any pointers to a table of conversion or the like would be helpful.

You should check out Bru'n Water since Citric is included in its array of acid choices.

that depends on the concentration. liquid acids can come in any variety. what do you have?

mabrungard said:

You should check out Bru'n Water since Citric is included in its array of acid choices.

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Yes, I have used Bru'n Water, but don't see a straight forward way of entering 1ml citric = X grams or 1 gram citric = X ml.

PDX_T said:

that depends on the concentration. liquid acids can come in any variety. what do you have?

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I have citric acid, it is in a powder or crystal like form.


Just thought a table would be an easy reference for acids that come in both solid and liquid.

It's not overly complicated.

If you want a 50% citric acid solution:

Take a 100ml flask, add 50g of citric acid, then add water and shake, to a level of 100ml.

As per here: http://www.physicsforums.com/showpost.php?p=2773613&postcount=3

MC

Ultimately, the acid quantities are specified in grams. The challenge is then to determine how much liquid acid of a given strength is needed to deliver the requisite number of grams of the acid. Starting with solid (you will never see lactic or phosphoric acid sold as solids though lactic does exist as a solid and phosphoric acid is made by dissolving phophorous pentoxide, a solid, in water) you weigh out the required amount of acid and add it to any reasonable volume of water (enough to dissolve it) and then add that. Or you make up a stock solution of a certain percentage w/v. If the stock solition contains 500 mg/L and you need 50 mg you then measure out 100 mL.

ajdelange said:

Ultimately, the acid quantities are specified in grams. The challenge is then to determine how much liquid acid of a given strength is needed to deliver the requisite number of grams of the acid. Starting with solid (you will never see lactic or phosphoric acid sold as solids though lactic does exist as a solid and phosphoric acid is made by dissolving phophorous pentoxide, a solid, in water) you weigh out the required amount of acid and add it to any reasonable volume of water (enough to dissolve it) and then add that. Or you make up a stock solution of a certain percentage w/v. If the stock solition contains 500 mg/L and you need 50 mg you then measure out 100 mL.

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Excellent advice.

It would indeed. Thanks.

So, for example, if I need 1 ml of 88% lactic acid to acidify my sparge water, how much 10% phosphoric acid would I need if I use that instead of the lactic acid? I have searched, but have not been able to find the relationship.

The proper way to do this is to determine the density of 88% lactic acid which is 1.206 g/cc. Thus 1 mL of 88% lactic acid contains 0.88*1.206 = 1.06 grams of lactic acid. Lactic acid has a gram equivalent weight of 90.08 so that 1.06 grams delivers 1.06/90.08 = 11.8 mEq protons. You multiply that by the GEW of phosphoric acid to determine how many grams of phosphoric acid are needed. Only catch here is that the GEW of phosphoric acid depends on the pH. The graph below shows what the values are (at 20 °C). Assuming that you are acidifying to pH 5.5 the GEW is apparently about 96 and you would use that value. 11.8*96 = 1133 mg or 1.122 grams. Given that your phosphoric acid is 10% w/w you would then need 11.22 grams of it. The density of 10% w/w phosphoric acid is 1.053 g/cc so you need 11.22/1.053 = 10.76 cc.