Acids, Bases and Salts Class 11 Chemistry Chapter 8 Notes, MCQs & One-Liners

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  1. Acids & bases have been used for centuries in labs and homes.
  2. Common household acids: Acetic acid (vinegar), Citric acid (citrus fruits), Phosphoric acid (carbonated drinks).
  3. Common household bases: Sodium hydroxide (drain cleaner), Ammonia (glass cleaner), Sodium hydrogen carbonate (baking soda).
  4. Acid definition: species with sour taste that produces hydrogen gas when reacting with active metals.
  5. Base definition: species with bitter taste and slippery texture.
  6. Neutralisation: when acids react with bases, they cancel each other’s properties, forming a neutral product.
  7. Oxides classification: metal oxides, non-metal oxides, and amphoteric oxides.
  8. Metal oxides (e.g., Na₂O, K₂O, CaO) dissolve in water to form alkaline solutions.
  9. Non-metal oxides (e.g., CO₂, SO₂, P₂O₅) dissolve in water to form acidic solutions.
  10. Amphoteric oxides (e.g., ZnO, Al₂O₃) react with both acids and bases.
  11. Bronsted-Lowry definition: an acid donates a proton (H⁺); a base accepts a proton.
  12. Acid-base reaction: involves transfer of a proton from acid to base.
  13. Acids (proton donors): HCl, HNO₃, H₂SO₄, H₂O, H₃O⁺, NH₄⁺.
  14. Bases (proton acceptors): NH₃, H₂O, OH⁻, Cl⁻, CO₃²⁻, HSO₄⁻.
  15. Amphoteric species: H₂O and HSO₄⁻ can act as both acid and base.
  16. Leveling Effect: water acts as a leveling solvent for strong acids.
  17. Lewis Definition (1923): Lewis acid accepts an electron pair; Lewis base donates an electron pair.
  18. Buffer solution: a solution whose pH remains nearly unchanged on dilution or addition of small amounts of acid or base.
  19. Types of buffer solutions: Acidic buffer (weak acid + salt with strong base) and Basic buffer (weak base + salt with strong acid).
  20. Buffer capacity: the amount of acid or base a buffer can neutralize before significant pH change occurs.
  21. Salt definition: a substance formed by the reaction of an acid and a base.
  22. Hydrolysis: a reaction between water and salt ions that produces an acidic or alkaline solution.
  23. Salt types: Salt of Strong acid & Strong base, Strong acid & Weak base, Weak acid & Strong base, Weak acid & Weak base.
  24. Table salt (NaCl) – essential in human diet.
  25. Epsom salt (MgSO₄) – laxative for constipation.
  26. Baking soda (NaHCO₃) – antacid for heartburn/acid indigestion.
  27. Washing soda (Na₂CO₃) – removes rigid stains in laundry.
  28. pH scale: ranges from 0 (very acidic) to 14 (very alkaline), with pH 7 indicating neutral solution.