Definitions [5]
Define pOH.
The pOH of a solution can be defined as the negative logarithm to the base 10, of the molar concentration of OH− ions in solution.
pOH = -log10[OH-]
Define pH.
The pH of a solution is defined as the negative logarithm to the base 10, of the concentration of H+ ions in solution in mol dm–3.
pH is expressed mathematically as
pH = -log10 [H+] or pH = -log10 [H3O+]
pH scale is a scale for measuring the hydrogen ion concentration in a solution.
Define Acidic buffer solution.
A solution containing a weak acid and its salts with strong base is called an acidic buffer solution.
Define buffer solution.
A buffer solution is defined as a solution which resists drastic changes in pH when a small amount of strong acid, strong base, or water is added to it.
Key Points
- The pH scale (0–14) measures the concentration of H⁺ ions in a solution; values < 7 indicate acids, > 7 indicate bases, and 7 is neutral.
- A universal indicator shows different colours at different pH levels, helping to determine the strength of an acid or base.
- Strong acids/bases produce more H⁺ or OH⁻ ions in solution, while weak acids/bases produce fewer ions at the same concentration.
Concepts [35]
- Concept of Equilibrium
- Solid-liquid Equilibrium
- Liquid-vapour Equilibrium
- Solid - Vapour Equilibrium
- Equilibrium Involving Dissolution of Solid in Liquids
- Equilibrium Involving Dissolution of Gases in Liquids
- General Characteristics of Equilibria Involving Physical Processes
- Equilibrium in Chemical Processes - Dynamic Equilibrium
- Law of Chemical Equilibrium and Equilibrium Constant
- Equilibrium Constant in Gaseous Systems
- Heterogeneous Equlibria
- Predicting the Extent of a Reaction
- Predicting the Direction of the Reaction
- Calculating Equilibrium Concentrations
- Relationship Between Equilibrium Constant K, Reaction Quotient Q and Gibbs Energy G
- Effect of Concentration Change
- Effect of Pressure Change
- Effect of Inert Gas Addition
- Effect of Temperature Change
- Effect of Catalyst
- Ionic Equilibrium in Solution
- Concept of Acid, Base, and Salt
- Arrhenius Concept of Acids and Bases
- Concept of Ionization of Acids and Bases
- The Ionization Constant of Water and Its Ionic Product
- The pH Scale
- Ionization Constants of Weak Acids
- Ionization of Weak Bases
- Relation Between Ka and Kb
- Di- and Polybasic Acids and Di- and Polyacidic Bases
- Factors Affecting Acid Strength
- Common Ion Effect in the Ionization of Acids and Bases
- Hydrolysis of Salts and the Ph of Their Solutions
- Buffer Solutions
- Concept of Solubility Equilibria of Sparingly Soluble Salts
