Salts
Basic chemistry concepts about salts. Types of salts, important salts and their uses for TNPSC exams.
Learning Content
🧂 Salts - Introduction!
Salt = acid + base → salt + water (neutralization)
📊 Types of salt - MASTER TABLE
| Type | Explanation | Example |
|---|---|---|
| Neutral salt | pH = 7 | NaCl, KNO₃ |
| acid salt | At pH < 7, H⁺ is present | NaHCO₃, NaHSO₄ |
| alkaline salt | At pH > 7, OH⁻ is present | Mg(OH)Cl |
| Double salt | 2 salts added | Potash alum |
| complex salt | Complex ion is present | [Cu(NH₃)₄]SO₄ |
🎯 Salt formation
| Acid + Alkali | HCl + NaOH → NaCl + H₂O |
| Acid + Metal | 2HCl + Zn → ZnCl₂ + H₂ |
| Acid + Carbonate | 2HCl + CaCO₃ → CaCl₂ + H₂O + CO₂ |
| Acid + Oxide | H₂SO₄ + CuO → CuSO₄ + H₂O |
💧 Hydrated Salts
| Gypsum | CaSO₄.2H₂O | 2 water molecule |
| Plaster of Paris | CaSO₄.½H₂O | ½ water molecule |
| Blue vitriol | CuSO₄.5H₂O | 5 water molecule |
| Green vitriol | FeSO₄.7H₂O | 7 water molecule |
| White vitriol | ZnSO₄.7H₂O | 7 water molecule |
⭐ Key Salts - TNPSC!
📊 Salts MASTER TABLE
| Salt | formula | Another name | benefit |
|---|---|---|---|
| Sodium Chloride | NaCl | Table salt, rock salt | Food, processing |
| Sodium Bicarbonate | NaHCO₃ | Baking soda, baking soda | Food, medicine, firefighting |
| Sodium carbonate | Na₂CO₃ | Washing soda, washing soda | Laundry, glass |
| Sodium hydroxide | NaOH | Caustic soda | Soap, paper |
| Calcium carbonate | CaCO₃ | Limestone, Chalkpeas, Marble | Construction, Cement |
| Calcium sulfate | CaSO₄.2H₂O | Gypsum | POP, Cement, Fertilizer |
| Potassium Nitrate | KNO₃ | Saltpeter, Eruption | Explosives, Fertilizer |
| Ammonium chloride | NH₄Cl | Innovation | Dry Cell, Dy |
| Copper sulfate | CuSO₄.5H₂O | Blue vitriol, zinc | Fungicide |
🔥 Sodium compounds - comparison
| Name | formula | Another name |
|---|---|---|
| cooking salt | NaCl | - |
| Baking soda | NaHCO₃ | Baking soda |
| Washing soda | Na₂CO₃ | Washing soda |
| Caustic soda | NaOH | - |
💡"Salt-Cooking-Laundry-Caustic"= NaCl - NaHCO₃ - Na₂CO₃ - NaOH
💎 Vitriols!
Vitriol = sulfate salts
📊 Vitriol MASTER TABLE
| Vitriol | formula | Color | benefit |
|---|---|---|---|
| Blue vitriol | CuSO₄.5H₂O | 🔵 Blue | Fungicide, electroplating |
| Green vitriol | FeSO₄.7H₂O | 🟢 Green | Ink production, fertilizer |
| White vitriol | ZnSO₄.7H₂O | ⚪ White | Eye medicine, Fertilizer |
💡"Blue-Copper, Green-Iron, White-Zinc"
🏗️ Calcium compounds
| Name | formula | benefit |
|---|---|---|
| Limestone | CaCO₃ | Cement, Sackpeas |
| Quick lime | CaO | White beat |
| Lime in water | Ca(OH)₂ | Lime water, whitewash |
| Gypsum | CaSO₄.2H₂O | POP, Cement |
| Plaster of Paris | CaSO₄.½H₂O | Fracture, sculpture |
| Bleaching powder | CaOCl₂ | Decolorizing, Disinfectant |
🎯 Alums
| Potash alum | K₂SO₄.Al₂(SO₄)₃.24H₂O | Water purification |
| Ammonia alum | (NH₄)₂SO₄.Al₂(SO₄)₃.24H₂O | Die process |
| Chrome alum | K₂SO₄.Cr₂(SO₄)₃.24H₂O | Tanning |
📝 TNPSC Main Questions & Shortcuts!
🎯 Frequently Asked Questions
| Q: Formula for cooking salt? | ✅ NaCl |
| Q: Baking soda formula? | ✅ NaHCO₃ |
| Q: Washing soda formula? | ✅ Na₂CO₃ |
| Q: Caustic soda formula? | ✅ NaOH |
| Q: Formula for blue vitriol? | ✅ CuSO₄.5H₂O |
| Q: Plaster of Paris formula? | ✅ CaSO₄.½H₂O |
| Q: Gypsum formula? | ✅ CaSO₄.2H₂O |
| Q: Explosive formula? | ✅ KNO₃ |
| Q: Navacharam Sutra? | ✅ NH₄Cl |
| Q: Bleaching powder formula? | ✅ CaOCl₂ |
| Q: Salt used for water purification? | ✅ Alum |
| Q: Salt in fire extinguisher? | ✅ NaHCO₃ |
💡 SUPER SHORTCUTS
🔵 Sodium compounds:
NaCl- Cooking salt
NaHCO₃- Baking soda
Na₂CO₃- Washing soda
NaOH— Caustic soda
🔴 Vitriol Colors:
🔵Blue= Cu (Copper)
🟢Green= Fe (Iron)
⚪White= Zn (Zinc)
🎯 Name - Formula QUICK MATCH
| Limestone | CaCO₃ |
| Quick lime | CaO |
| Lime in water | Ca(OH)₂ |
| Gypsum | CaSO₄.2H₂O |
| POP | CaSO₄.½H₂O |
| Bleaching powder | CaOCl₂ |
📋 Memory TRICKS
🎯Gypsum → POP: 2H₂O → ½H₂O (water decreases!)
🎯POP + water = harden(for fracture)
💡"U-cha-cha-ka"= salt-cooking-laundry-caustic (Na compounds)
💡"Ni-se, b-e, ve-tu"= blue-copper, green-iron, white-zinc
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