When is kb greater than kc

K p and K c are equilibrium constants of ideal gas mixtures considered under reversible reactions. K p is an equilibrium constant written with respect to the atmospheric pressure and the K c is the equilibrium constant used with respect to the concentrations expressed in molarity.

The Kp Kc relation can be derived by understanding what are Kp and Kc. The relation between K p and K c is given by following simple derivation. To derive the relation between K p and K c, consider the following reversible reaction:. K c is the equilibrium constant for a reversible reaction and it is given by,. Similarly, K p is the equilibrium constant in terms of atmospheric pressure and is given by the expression:.

To derive relation between K p and K c, consider the ideal gas equation,. Use known concentrations to solve for the equilibrium constants. The Equilibrium Constant Equilibrium reactions are those that do not go to completion, but are in a state where the reactants are reacting to yield products and the products are reacting to produce reactants. There are some rules about writing equilibrium constant expressions that need to be learned: Concentrations of products are multiplied on the top of the expression.

Concentrations of reactants are multiplied together on the bottom. Coefficients in the equation become exponents in the equilibrium constant expression. Solids, liquids, and solvents are assigned a value of 1, so their concentrations do not affect the value of K.

Equilibrium Constant Expressions The equilibrium constant value is the ratio of the concentrations of the products over the reactants. If K eq is very large , the concentration of the products is much greater than the concentration of the reactants. The reaction essentially "goes to completion"; all, or most of, the reactants are used up to form the products. If K eq is very small , the concentration of the reactants is much greater than the concentration of the products.

Hence the ionization equilibrium lies virtually all the way to the right, as represented by a single arrow:. In contrast, acetic acid is a weak acid, and water is a weak base. Similarly, in the reaction of ammonia with water, the hydroxide ion is a strong base, and ammonia is a weak base, whereas the ammonium ion is a stronger acid than water.

Hence this equilibrium also lies to the left:. All acid—base equilibria favor the side with the weaker acid and base. Thus the proton is bound to the stronger base. Two species that differ by only a proton constitute a conjugate acid—base pair.