The pH Scale and Salts Chemistry

The pH Scale: Developed by Sørensen to express hydrogen ion concentration conveniently:

• Strongly acidic: pH 0 to 3 (e.g., gastric juice, battery acid).

• Weakly acidic: pH 4 to 6 (e.g., vinegar, coffee, milk).

• Neutral: pH 7.0 (pure distilled water at 25°C).

• Weakly basic: pH 8 to 10 (e.g., baking soda, sea water).

• Strongly basic: pH 11 to 14 (e.g., bleach, drain cleaner, NaOH).

Salts: Ionic compounds composed of a positive metallic cation and a negative acid radical anion. Classification by solubility:

• Soluble Salts: All nitrates (NO3-), all acetates (CH3COO-), all sodium (Na+), potassium (K+), and ammonium (NH4+) salts.

• Insoluble Salts (Precipitates): Silver chloride (AgCl, white), Lead iodide (PbI2, yellow), Barium sulfate (BaSO4, white), Calcium carbonate (CaCO3, white).