Water Hardness: An Overview

Hard Water:

• Temporary hard water: Contains Mg²⁺, Ca²⁺, HCO₃^– ions.

• Permanent hard water: Contains Mg²⁺, Ca²⁺, Cl^–, SO₄^2- ions.

Addressing Hard Water:

• Two preferred substances: Na₂CO₃, Na₃PO₄ (or K₂CO₃, K₃PO₄)

Important Compounds:

• Anhydrous gypsum: CaSO₄

• Plaster of Paris: CaSO₄.H₂O

• Alum: K₂SO₄.Al(SO₄)₃.24H₂O or KAl(SO₄)₂.12H₂O

Chemical Properties:

• Least reactive metal: Fe

• Gases at room temperature: HCHO, CH₃CHO

• NaHCO₃: Used for treating indigestion, baking powder

• Zn₃P₂: Used as a rat poison

• Starch and Cellulose: Do not react with Cu(OH)₂

• Sucrose, starch, cellulose: Do not participate in the reaction with AgNO₃/NH₃

• Monohydric alcohols: Do not react with base solutions

Fatty Acids:

• Palmitic acid: C₁₅H₃₁COOH

• Stearic acid: C₁₇H₃₅COOH

• Oleic acid: C₁₇H₃₃COOH

• Linoleic acid: C₁₇H₃₁COOH

Carbohydrates:

• Monosaccharide: Glucose, Fructose (C₆H₁₂O₆)

• Disaccharide: Sucrose, Maltose (C₁₂H₂₂O₁₁)

• Polysaccharide: Starch, Cellulose (C₆H₁₀O₆)n

This translation provides a concise overview of the concepts related to water hardness, important compounds, chemical properties, fatty acids, and carbohydrates. It uses appropriate chemical formulas and clear language for better understanding.