ACIDS, BASES AND SALTS

  Al D. Deacon 

Founder: Gold'N Geniuz 

Physicist and Educator 



1. Define Acid, Acid Anhydride, Base, Alkali, Salt, Acidic, Basic, Amphoteric, and Neutral Oxides

  • Acid: A substance that donates H⁺ ions in solution (e.g., HCl, H₂SO₄).
  • Acid Anhydride: A non-metal oxide that reacts with water to form an acid (e.g., SO₃ + H₂O → H₂SO₄).
  • Base: A substance that accepts H⁺ ions or neutralizes acids (e.g., MgO, CuO).
  • Alkali: A base that is soluble in water, producing OH⁻ ions (e.g., NaOH, KOH).
  • Salt: A compound formed when the hydrogen in an acid is replaced by a metal or ammonium ion (e.g., NaCl, CuSO₄).
  • Acidic Oxide: A non-metal oxide that reacts with water to form an acid (e.g., CO₂, SO₂).
  • Basic Oxide: A metal oxide that reacts with acids to form a salt and water (e.g., MgO, CaO).
  • Amphoteric Oxide: An oxide that reacts with both acids and bases (e.g., Al₂O₃, ZnO).
  • Neutral Oxide: A non-metal oxide that is neither acidic nor basic (e.g., CO, NO).

2. Relate Acidity and Alkalinity to the pH Scale

  • pH Scale: Ranges from 0 to 14, where:
    • pH < 7 → Acidic
    • pH = 7 → Neutral
    • pH > 7 → Alkaline
  • Indicators:
    • Litmus: Red in acid, blue in alkali
    • Phenolphthalein: Colorless in acid, pink in alkali
    • Methyl Orange: Red in acid, yellow in alkali

3. Discuss the Strength of Acids and Alkalis on the Basis of Their Completeness of Ionization

  • Strong Acids: Fully ionize in solution (e.g., HCl, H₂SO₄, HNO₃).
    • HCl → H⁺ + Cl⁻
  • Weak Acids: Partially ionize in solution (e.g., CH₃COOH).
    • CH₃COOH ⇌ CH₃COO⁻ + H⁺
  • Strong Alkalis: Fully ionize in solution (e.g., NaOH, KOH).
    • NaOH → Na⁺ + OH⁻
  • Weak Alkalis: Partially ionize (e.g., NH₃).
    • NH₃ + H₂O ⇌ NH₄⁺ + OH⁻

4. Investigate the Reactions of Non-Oxidizing Acids

  • Definition: Non-oxidizing acids do not contain strong oxidizing agents (e.g., HCl, H₂SO₄).
  • Reactions:
    • With Metals: Acid + Metal → Salt + H₂
      • Zn + HCl → ZnCl₂ + H₂
    • With Metal Oxides: Acid + Metal Oxide → Salt + Water
      • H₂SO₄ + CuO → CuSO₄ + H₂O
    • With Carbonates: Acid + Carbonate → Salt + Water + CO₂
      • HCl + CaCO₃ → CaCl₂ + H₂O + CO₂

5. List Examples of Acids in Living Systems

  • Stomach Acid: HCl (digestion)
  • Amino Acids: Building blocks of proteins
  • Lactic Acid: Formed in muscles during exercise
  • Citric Acid: Found in citrus fruits
  • DNA & RNA: Contain nucleic acids

6. Investigate the Reaction of Bases with Ammonium Salts

  • Reaction: Base + Ammonium Salt → Salt + Water + Ammonia Gas
    • Example:
      • NH₄Cl + NaOH → NaCl + H₂O + NH₃ (gas)
    • Test for Ammonia: Pungent smell, turns red litmus blue

7. Identify an Appropriate Method of Salt Preparation Based on Solubility

  • Soluble Salts (e.g., NaCl, KNO₃):
    • Neutralization (acid + base)
    • Reaction of acid with metal or carbonate
  • Insoluble Salts (e.g., BaSO₄, AgCl):
    • Precipitation Reaction (mixing two soluble salts)
    • Example:
      • BaCl₂ + H₂SO₄ → BaSO₄ (ppt) + 2HCl

8. List the Uses and Dangers of Salts

Uses

  • NaCl: Preserving food, seasoning
  • CaCO₃: Making cement, antacids
  • KNO₃: Fertilizers, explosives
  • Na₂CO₃: Soap making, glass production

Dangers

  • Lead(II) salts: Toxic, cause lead poisoning
  • Excess NaCl: High blood pressure
  • AgNO₃: Corrosive, can cause burns

9. Distinguish Between Acid Salts and Normal Salts

  • Normal Salt: Formed when all H⁺ ions in an acid are replaced by metal ions (e.g., Na₂SO₄, KCl).
  • Acid Salt: Formed when only some H⁺ ions are replaced (e.g., NaHSO₄, NaHCO₃).

10. Investigate Neutralization Reactions Using Indicators and Temperature Changes

  • Definition: Acid + Base → Salt + Water
  • Experiment:
    • Titration (using phenolphthalein or methyl orange)
    • Temperature Change: Neutralization is exothermic
    • Example:
      • HCl + NaOH → NaCl + H₂O

11. Perform Calculations Using Volumetric Analysis Data

  • Formula:
    • Moles = Concentration (mol/L) × Volume (L)
  • Titration Calculation Example:
    • 25.0 cm³ of 0.100 M HCl neutralizes 30.0 cm³ of NaOH
    • Equation: HCl + NaOH → NaCl + H₂O
    • Moles of HCl = 0.100 × (25.0/1000) = 0.0025 mol
    • Mole ratio HCl:NaOH = 1:1
    • Moles of NaOH = 0.0025 mol
    • Concentration of NaOH = 0.0025 / (30.0/1000) = 0.0833 M


Comments

Post a Comment