Properties of acids and bases: Acids:

1. Sour taste
2. pH less than 7
3. React with metals to produce hydrogen gas
4. Turn blue litmus paper red
5. Conduct electricity when dissolved in water

Bases:

1. Bitter taste and slippery feel
2. pH greater than 7
3. React with acids to form salts
4. Turn red litmus paper blue
5. Conduct electricity when dissolved in water

Theories of acids and bases:

1. Arrhenius theory: Acids produce H+ ions, bases produce OH- ions in water
2. Brønsted-Lowry theory: Acids are proton donors, bases are proton acceptors
3. Lewis theory: Acids are electron pair acceptors, bases are electron pair donors
4. Solvent system theory: Defines acids and bases based on the solvent used
5. Lux-Flood theory: Focuses on oxide ion transfer in non-aqueous systems
6. Usanovich theory: Broadest definition, includes redox reactions

pH calculation and representation:

1. Definition: pH = -log[H+], where [H+] is the concentration of hydrogen ions
2. Scale: Ranges from 0 (most acidic) to 14 (most basic), with 7 being neutral
3. Logarithmic scale: Each unit change represents a 10-fold change in H+ concentration
4. pOH: Represents hydroxide ion concentration, pH + pOH = 14
5. Indicators: Substances that change color at specific pH values
6. Importance: Critical in biological systems, chemical processes, and environmental science