[gfabster]

I was just wondering, is it is possible to calculate the pH of a drink if its acid concentration was discovered through an acid-base titration?

I was assigned a titration lab in which I was to titrate a drink (containing citric acid) with sodium hydroxide and then calculate the citric acid concentration of the drink.

I am aware that the pH of the drink could easily be revealed using a pH test, but I wanted to know if it was possible to determine this algebraically.

Thank you in advance.

[Borek]

If you know dissociation constants and concentrations of all Bronsted-Lewis acids present in the solution then yes, it is possible to calculate pH.

Doesn't mean it is a simple task.

[Big-Daddy]

Citric acid is triprotic so you'll need the three acid dissociation constants. If you also have the concentration c₀ you just need to write the mass balance (conservation of the anion), charge balance for the whole system, and equilibrium constant expressions and you can calculate [H⁺]. Approximations will often follow, e.g. if the acid is concentrated then you can neglect [OH^-] and K_w, though I cannot think of any other decent approximations for citric acid... since the Ka values are so close.

[Vidya]

I was just wondering, is it is possible to calculate the pH of a drink if its acid concentration was discovered through an acid-base titration?

I was assigned a titration lab in which I was to titrate a drink (containing citric acid) with sodium hydroxide and then calculate the citric acid concentration of the drink.

I am aware that the pH of the drink could easily be revealed using a pH test, but I wanted to know if it was possible to determine this algebraically.

Thank you in advance.

Titration will give you the concentration of the acid and from this concentration you can work out the concentration of H+ using ICE table .Negative logarithm of [H+] is the pH of the solution.

[Big-Daddy]

Titration will give you the concentration of the acid and from this concentration you can work out the concentration of H+ using ICE table .Negative logarithm of [H+] is the pH of the solution.

Will ICE work here? It's a triprotic acid with close-together pKa values...