Acids
Definition
- Acids are substances that donate H+ ions or release hydrogen gas when reacted with metals.
- Acids turn blue litmus red.
Properties
- Sour taste
- Corrosive nature
- Turn blue litmus red
- React with bases to form salts and water
Examples
- Hydrochloric acid (HCl)
- Sulphuric acid (H2SO4)
- Nitric acid (HNO3)
- Acetic acid (CH3COOH)
Bases
Definition
- Bases are substances that accept H+ ions or release hydroxide ions (OH-).
- Bases turn red litmus blue.
Properties
- Bitter taste
- Slippery feel
- Turn red litmus blue
- React with acids to form salts and water
Examples
- Sodium hydroxide (NaOH)
- Calcium hydroxide (Ca(OH)2)
- Magnesium hydroxide (Mg(OH)2)
- Ammonium hydroxide (NH4OH)
Salts
Definition
- Salts are substances formed by the reaction of acids and bases.
- Salts are ionic compounds.
Properties
- Salts have a neutral pH
- Salts are crystalline solids
- Salts dissolve in water to give a neutral solution
Examples
- Sodium chloride (NaCl)
- Sodium sulphate (Na2SO4)
- Calcium carbonate (CaCO3)
- Ammonium nitrate (NH4NO3)
pH Scale
Definition
- The pH scale is a measure of the concentration of hydrogen ions in a solution.
- pH scale ranges from 0 to 14.
pH Values
- pH 0-1: Strongly acidic
- pH 2-3: Acidic
- pH 4-5: Weakly acidic
- pH 6-7: Neutral
- pH 8-9: Weakly basic
- pH 10-12: Basic
- pH 13-14: Strongly basic
Important Reactions
Acid-Base Reactions
- Acid + Base → Salt + Water
- HCl + NaOH → NaCl + H2O
Neutralization Reactions
- Acid + Base → Salt + Water
- H2SO4 + Ca(OH)2 → CaSO4 + H2O
These notes cover the key concepts and properties of acids, bases, and salts, as well as the pH scale and important reactions.
