Question

I'm trying to replace vinegar with sodium diacetate in a recipe, and I would like to understand better what is happening from a chemical point of view.

What I imagine happens when I add sodium diacetate to the pot:

NaH(C₂H₃O₂)2+H₂O⟶(C₂H₄O₂)₂+NaOH

But what happens to the sodium hydroxide? It's alkaline in a acidic solution so it should react somehow?

Also if I know that 100 ml
of vinegar contains 4 g
of acetic acid, how much sodium diacetate should I add to substitute the vinegar?

Answer 1

Sodium diacetate dissociates in solution releasing diacetate ions that can react to form acetic acid and hydroxide ions, making the solution slightly basic. To substitute vinegar in a recipe, calculate the equivalent molar amount of sodium diacetate to match the acetic acid content in vinegar, considering the stoichiometry of the reaction.

Step-by-step explanation:

When you add sodium diacetate (NaH(C₂H₃O₂)₂) to a solution, it dissociates into sodium ions (Na+) and diacetate ions (C₂H₃O₂-). The diacetate ion can further react with water to produce two molecules of acetic acid (C₂H₄O₂) and hydroxide ions (OH-), which increases the pH of the solution by making it slightly basic.

However, since acetic acid is a weak acid, the effect on the pH is not as substantial as it would be with a strong base. In a recipe, if 100 ml of vinegar contains 4 g of acetic acid, to replace vinegar with sodium diacetate, you need to consider the molar masses and the fact that sodium diacetate will yield two moles of acetic acid per mole of sodium diacetate.

Thus, you should add an equivalent molar amount of sodium diacetate to achieve the same number of moles of acetic acid as present in vinegar. Due to the counteracting effect of the formed sodium hydroxide in the chemical reaction, your recipe's acidity might be slightly different from that of the original vinegar.