Chapter: Acids, Bases and Salts
GSEB Standard 10 Science – Chapter 2
📘 Overview:
This chapter focuses on the chemical nature, properties, and reactions of acids, bases, and salts, which are essential in both everyday life and industrial applications. It explains how these substances interact with each other and with indicators, and how they are used in real-world contexts such as medicine, agriculture, and food.
🧪 Key Concepts Covered:
1. Acids
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Taste sour, turn blue litmus red.
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Examples: HCl (hydrochloric acid), H₂SO₄ (sulphuric acid), CH₃COOH (acetic acid)
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Found in: lemons (citric acid), vinegar (acetic acid), curd (lactic acid)
2. Bases
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Taste bitter, feel soapy, turn red litmus blue.
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Examples: NaOH (sodium hydroxide), KOH (potassium hydroxide), NH₄OH (ammonium hydroxide)
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Found in: soap, limewater, toothpaste
3. Indicators
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Substances that change color in acidic or basic solutions.
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Natural indicators: Litmus, turmeric, China rose
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Synthetic indicators: Methyl orange, phenolphthalein
4. Chemical Reactions of Acids and Bases
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Reaction with metals:
Acid + Metal → Salt + Hydrogen gas -
Reaction with metal carbonates/bicarbonates:
Acid + Metal carbonate → Salt + Water + CO₂ -
Neutralization Reaction:
Acid + Base → Salt + Water -
Reaction with oxides:
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Acid + Metal oxide → Salt + Water
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Base + Non-metal oxide → Salt + Water
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5. Strength of Acids and Bases
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Measured using the pH scale (0–14)
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pH < 7: Acidic
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pH = 7: Neutral
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pH > 7: Basic
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Universal indicator shows a range of colors for different pH levels.
6. Salts
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Formed from neutralization reactions
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Examples:
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Sodium chloride (NaCl) – common salt
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Sodium carbonate (Na₂CO₃) – washing soda
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Sodium hydrogen carbonate (NaHCO₃) – baking soda
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Plaster of Paris (CaSO₄·½H₂O) – used in casting
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7. Uses in Daily Life
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Baking soda – in cooking and medicine (antacid)
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Washing soda – in cleaning and softening water
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Plaster of Paris – for making casts and statues
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Common salt – in food and preservation
