What is the relationship between acid dissociation and pH?

Answer 1

The dissociation constant, or Kw of water, is related to the pH of a neutral solution in that the pKw is equal to 14 which is equal to the sum of the pH and the pOH. Because the pKw of water is equal to 14, a neutral solution which has the same concentration of hydroxide and hydrogen ions will have a pH of 7.

Answer 2

What is the relationship between acid dissociation and ph?

When an acid dissolves in water it forms Hydronium ions (H3O^+1) and the anion of the acid. The hydronium ion is the ion that removes rust from metals. It is the attacker, the anion is present just to balance the +1 charge.

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Dissociation means, when the acid is dissolved in water, the H^+1 ion separates from the anion of the acid producing H3O+1 ions and the anion of the acid. Strong acids are strong because they release most of the H+1ions to react. A weak acid, such as acetic acid (vinegar) releases very few H+1's to react. Acetic acid (HC2H3O2), has a dissociation constant of 1.8 * 10-5.

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The dissociation constant, Ka, describes the number of H+ ions that will separate from the ion compared to the number of acid molecules present in the beginning.

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The equation for dissolving ascetic acid in water is

HC2H3O2 + H2O = H3O+1 + C2H3O2^-1

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Here is the general equation for an acid with 1 H.

Ka = [H^+1] * [A^-1] ÷ [HA]

The brackets […] mean moles per liter.

Ka is the dissociation constant.

We use this equation to determine the concentration of H3O+1 ion in moles/liter to determine pH.

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Ka for acetic acid = 1.8 * 10-5

Below is the equation for acetic acid dissociating in water.

HC2H3O2 + H2O = H3O+1 + C2H3O2^-1

When one acetic acid molecule dissociates it produces 1 H3O+1 ion and 1 C2H3O2^-1 ion, so the concentration of H3O+1 ions equals the concentration of C2H3O2^-1 ions.

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Let x = the concentration of H3O+1 ions produced. The C2H3O2^-1 ion concentration also equals x, since one acetic acid molecule dissociates producing 1 H3O+1 ions and 1 C2H3O2^-1 ion

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For a 0.1 molar solution of acetic acid the dissociation equation is as follows:

Ka = [H3O+1] * [C2H3O2^-1] ÷ [HC2H3O]

1.8 * 10-5 = [x]*[x] ÷ 0.1

1.8 * 10-5 = x^2 ÷ 0.1

1.8 * 10-6 = x^2

x = (1.8 * 10-6)^0.5

x = 0.00424

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x = [H3O+1, the concentration of H3O+1 ions produced

pH = -log of [H3O+1] ions in solution

pH = -log 0.00424

pH = 2.37

A .1 molar solution of HCl, which is a strong acid, assuming it completely dissociates, has a pH = 1

This means the smaller the dissociation constant, the higher the pH. The higher the pH, the less acidic the solution is.

Answer 3

Acid dissociation is the process by which an acid releases a hydrogen ion in water. The concentration of hydrogen ions released during this process affects the pH of a solution - the higher the concentration of hydrogen ions, the lower the pH. Therefore, acid dissociation directly impacts the pH of a solution.

Answer 4

Describe the relationship between Hydrogen ions and pH?