Acids, Bases and Salts, Chapter 2, NCERT Notes Class 10th


Here are simplified notes on Acids, Bases, and Salts:


Acids:

- Definition: Acids are substances that release hydrogen ions (H⁺) when dissolved in water.

- Examples: Lemon juice (citric acid), vinegar (acetic acid), stomach acid (hydrochloric acid).

- Properties: Sour taste, turn blue litmus paper red, react with metals to release hydrogen gas.


Bases:

- Definition: Bases are substances that release hydroxide ions (OH⁻) when dissolved in water, or accept H⁺ ions.

- Examples: Soap, baking soda (sodium bicarbonate), ammonia (NH₃).

- Properties: Bitter taste, feel slippery or soapy, turn red litmus paper blue.


Neutralization Reaction:

- When an acid reacts with a base, they neutralize each other to form salt and water.

- Example: Hydrochloric acid (HCl) + Sodium hydroxide (NaOH) → Sodium chloride (NaCl) + Water (H₂O).


pH Scale:

- Measures acidity or basicity of a solution.

- Range from 0 to 14: 0-6.9 is acidic, 7 is neutral, 7.1-14 is basic.

- Examples: Battery acid (pH 1), pure water (pH 7), bleach (pH 12).


Salts:

- Definition: Salts are compounds formed from the reaction of an acid with a base.

- Examples: Sodium chloride (NaCl), calcium carbonate (CaCO₃), potassium nitrate (KNO₃).

- Properties: Often crystalline solids, can be soluble or insoluble in water.


Common Salt:

- Sodium chloride (NaCl), obtained from seawater or mined from salt deposits.

- Used in cooking, preserving food, and as a seasoning.


Types of Salts:

- Normal Salts: Formed from strong acid + strong base (e.g., NaCl).

- Acidic Salts: Formed from strong acid + weak base (e.g., NaHSO₄).

- Basic Salts: Formed from weak acid + strong base (e.g., NaHCO₃).


Uses of Salts:

- Food preservation, flavoring, and seasoning.

- Industrial processes, water softening, and agriculture.


Importance in Nature:

- Acids and bases are crucial in biochemical processes (e.g., digestion).

- pH balance is essential for aquatic ecosystems and soil fertility.


Acid Rain:

- Formed when sulfur dioxide (SO₂) and nitrogen oxides (NOâ‚“) react with water in the atmosphere.

- Causes environmental damage to vegetation, water bodies, and buildings.


Summary:

- Acids release H⁺ ions, taste sour, and turn blue litmus paper red.

- Bases release OH⁻ ions, taste bitter, and turn red litmus paper blue.

- Salts are compounds from acid-base reactions, used widely in daily life.


Understanding acids, bases, and salts helps explain many chemical reactions and their impact on our environment and daily activities.

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