Chemistry Forum

To adjust the pH of the mixture, 5 ml of propionic acid was added to 1 liter of mixture. But I want to use citric acid instead of propionic acid. How many grams of citric acid should I use instead of 5 ml of propionic acid to have the same effect on pH?

Is it possible to make such a calculation without measuring with a pH meter?

Datas of propionic acid missing. Concentration, percentage. If this is known convert ml to g by using specific gravity. Then convert to mole.
Citric acid is a tricarbonic acid, so you need 1/3 of mole. Convert this back to mass by using molar mass of citric acid.

Hello;
Sorry for the missing information.
According to bottle;
Propionic acid is ACS reagent, ≥99.5%. Density: 0.992 g/cm3

So 5 ml propionic acid is equal to 4.96 g propionic acid

Molar mass of propionic acid = 74.078 g/mol
4.96 g propionic acid = 0.0669 mol

Molar mass of citric acid = 192.124 g/mol

At this point, I'm not sure I understood your message correctly and made the calculations correctly.

0.0669 mol citric acid = 12.853 g
12.853/3 = 4.284 g

Then, if I use 4.28 g of citric acid instead of 4.96 g of propionic acid in the mixture, will I get the same result at the final pH value?

Theoretical yes.
But citric acid is also a buffer. To get right value use a pH Meter and adjust pH.

Thank you.

I'm just asking to get detailed information about the subject.

Molar mass of H₂SO₄ = 98.08 g/mol
0.0669 mol HCl = 6.561 g
The maximum concentration of H₂SO₄ in aqueous solutions is 98% (w/w)
In this case, I should use 6.694 grams of sulfuric acid (98%) instead of 4.96 grams of propionic acid.

But isn't sulfuric acid a much stronger acid than propionic acid? But even though it was strong, I had to use it more.

Isn't this calculation you gave valid for all acids? Which topic article should I read to get more detailed information about this topic?

Thank you again.

You have to compare pkS values.
And propionic acid and citric acid are weak acids, sulfuric is a very strong acid.
And it also matters what is in the water. If you have strong or weak bases.

To determine how many grams of citric acid can replace propionic acid in a given context, we need to consider their chemical properties, particularly their acidity, since both are used to adjust pH in applications like food preservation, cosmetics, or chemical processes.

Already discussed. No need to fill with more unnecessary words.