Question

EXTREME HURRY!! State the ionization constant expression Ka for lactic acid. Given: pKa = 3.85 and Ka = 1.4*10^-4 mol dm^-3

What is pKa? How does it differ from pH? Same thing with Ka - please help soon!

Answer 1

Ok. To find the ionization constant expression, let's write out the chemical equation for the dissociation of lactic acid in water:\[C_3H_6O_3(aq)+H_2O(l) \rightarrow C_3H_5O_3^-(aq)+H_3O^+(aq)\]So that means the acid dissociation constant expression is:\[K_a=\frac{[C_3H_5O_3^-][H_3O^+]}{[C_3H_6O_3]}\]

Answer 2

Ka is defined as exactly what we just did. The Ka of some acid, A, is the ratio of the product of the concentrations of the aqueous products divided by the product of the concentrations of the aqueous reactants when you dissociate acid A in water.

Answer 3

pKa is simply defined as:\[pKa=-\log(K_a)\]

Answer 4

pKa is a measure of the degree of the dissociation of an acid, while pH is the measure of the concentration of hydronium ions in a solution.