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ICE

ICE table

ICE stands for "Initial, Change, Equilibrium". These tables are useful for working out concentrations of reactants and products in equilibrium.

The three steps can occur when dissolving an acid or an alkali in water, for instance.

A table that can be used to calculate the concentrations of acid, hydronium ions, and conjugate base at the three different stages of a reaction of an acid with water. The reaction stages are I, the initial phase, C the change phase, and E, the equilibrium phase. The table contents are as follows. Acid concentrations: during initial phase, equal to C subscript A, which is the initial acid concentration, during change phase, equals negative X, which is the concentration change during dissociation, during the equilibrium phase, equals C subscript A minus X. Hydronium ion concentrations: during initial phase, equals zero, during the change phase, equals positive X, and during the equilibrium phase, equals X. Conjugate base concentration: during the initial phase, equals zero, during the change phase, equals positive X, and during the equilibrium phase, equals X. For a strong acid, X is equal to the initial concentration of the acid. For a weak acid, X must be calculated using the formula for the acid dissociation constant, which is Ka equals the concentration of hydronium ions times the concentration of conjugate base, divided by the acid concentration. After substituting the concentration values for those located in the equilibrium phase of the ICE chart, the equation becomes Ka equals X times X divided by the initial concentration of acid minus X. This equation can then be rearranged to X squared plus the acid dissociation constant times X minus the acid dissociation constant times the initial concentration of acid equals zero. This equation can then be solved for X and the ICE table can be filled out with the value of X.

Figure 1. ICE Table for Acids.

In this table, Ca stands for the initial concentration of the acid and x is the amount that reacts (negative if it disappears and positive if it is formed). This amount can be calculated from the acid dissociation constant (Ka)c a stands for the initial concentration of the acid and x is the amount that reacts, negative if it disappears and positive if it is formed. This amount can be calculated from the acid dissociation constant by isolating x after substituting the concentrations for those obtained in the equilibrium (E-row in the table).

Notice that x can be approximated to Ca c a when it is a strong acid since they are totally dissociated.

The ICE table can also be used for a reaction of a base in water.

Acids and bases

Referred from:

Article
The acid and base dissociation constants
Article
ICE Bases