Associated with any weak acid or weak base is a K_{a} or K_{b} value respectively.

## Understanding Ka and Kb Expressions

Weak acids possess a K_{a} value less than 1, while weak bases possess a K_{b} value less than 1. The equilibrium expressions of K_{a} and K_{b} are the same as other equilibrium constants we’ve seen.

## Understanding Ka and Kb

The greater the K_{a} value then the stronger the acid, while the greater the K_{b} the stronger the base. K_{a} and K_{b} are connected by the following equation:

If the Kb of NH_{3} is 1.76 x 10^{-5}, determine the acid dissociation constant of its conjugate acid.

^{-10}

^{-10}

^{-9}

^{-14}

## Ka and Kb Example 1

## What is the equilibrium constant for the following reaction and determine if reactants or products are favored

## Which of the following solutions will have the lowest pH

Which Bronsted-Lowry base has the greatest concentration of hydroxide ions?

_{2}H

_{8}N

_{2}(Kb = 8.3 x 10

^{-5})

_{5}H

_{5}N (Kb = 1.7 x 10

^{-9})

_{3})

_{3}N (Kb = 1.0 x 10

^{-6})

_{3}H

_{7}NH

_{2}(Kb = 3.5 x 10

^{-4})

_{6}H

_{5}NH

_{2}(Kb = 3.9 x 10

^{-10})

Which Bronsted-Lowry acid has the weakest conjugate base?

_{a}= 2.0 x 10

^{-4})

_{a}= 3.5 x 10

^{-4})

_{3}(K

_{a}= 2.5 x 10

^{-5})

_{2}CO

_{3}(K

_{a}= 4.3 x 10

^{-7})

- The following diagrams represent aqueous solutions of three acids, HX, HY, and HZ. The water molecules have be...
- Classify each acid as strong or weak. If the acid is weak, write an expression for the acid ionization constan...
- The following pictures represent solutions of three salts NaA (A- = X-, Y-, or Z-); water molecules and Na+ i...
- The following picture represents the hydrated metal cation M1H2O26 n + , where n = 1, 2, or 3. (a) Write a ba...
- The following picture represents the hydrated metal cation M1H2O26 n + , where n = 1, 2, or 3. (b) Does t...
- Rank the solutions in order of decreasing [H3O+]: 0.10 M HCl; 0.10 M HF; 0.10 M HClO; 0.10 M HC6H5O.
- Write the chemical equation and the Ka expression for the acid dissociation of each of the following acids in ...
- Choose from the conjugate acidâ€“base pairs HSO4- >SO42-, HF>F-, and NH4+>NH3 to complete the following...
- The hypochlorite ion, ClO-, acts as a weak base. (a) Is ClO- a stronger or weaker base than hydroxylamine?
- Write the chemical equation and the Kb expression for the reaction of each of the following bases with water: ...
- Write the chemical equation and the Kb expression for the reaction of each of the following bases with water: ...
- Use the acid-dissociation constants in Table 16.3 to arrange these oxyanions from strongest base to weakest: S...
- Which is the stronger base, the acetate ion or the hypochlorite ion?
- Given that Ka for acetic acid is 1.8 * 10-5 and that for hypochlorous acid is 3.0 * 10-8, which is the strong...
- Calculate Kb values for CH3COO- and ClO-.
- Given that Kb for ammonia is 1.8 * 10-5 and that for hydroxylamine is 1.1 * 10-8, which is the stronger base?
- Pyridinium bromide 1C5H5NHBr2 is a strong electrolyte that dissociates completely into C5H5NH+ and Br-. An aqu...
- The Kb for methylamine 1CH3NH22 at 25 Â°C is given in Appendix D. (a) Write the chemical equation for the equil...
- Write equations showing how each weak base ionizes water to form OH-. Also write the corresponding expression ...
- Write equations showing how each weak base ionizes water to form OH-. Also write the corresponding expression ...
- Write equations showing how each weak base ionizes water to form OH-. Also write the corresponding expression ...
- Salts containing the phosphate ion are added to municipal water supplies to prevent the corrosion of lead pip...
- Which, if any, of the following statements are true? (a) The stronger the base, the smaller the pKb. (b) The...
- Butyric acid is responsible for the foul smell of rancid butter. The pKa of butyric acid is 4.84. (a) Calculat...
- Write a balanced net ionic equation and the corresponding equilibrium equation for the reaction of the follow...
- The amino acid glycine 1H2NÂ¬CH2Â¬COOH2 can participate in the following equilibria in water: H2NÂ¬CH2Â¬COOH + H2O...
- Using values of Kb in Appendix C, calculate values of Ka for each of the following ions. (a) Propylammonium io...
- Using values of Ka in Appendix C, calculate values of Kb for each of the following ions. (a) Fluoride ion, F...
- Nicotine 1C10H14N22 can accept two protons because it has two basic N atoms 1Kb1 = 1.0 * 10-6; Kb2 = 1.3 * 10-...
- Using dissociation constants from Appendix D, determine the value for the equilibrium constant for each of the...