Introduction to Acids, Bases, and Salts

Introduction to Acids, Bases, and Salts

• Acids, bases, and salts are fundamental chemical classes crucial in many chemical reactions and biological processes.

Acids

• Acids are substances that donate a proton (H+) in a chemical reaction.
• Common properties of acids include:
  • Sour taste (e.g., lemon juice, vinegar)
  • Ability to react with metals, releasing hydrogen gas
  • Ability to conduct electricity in aqueous solution
  • Turn blue litmus paper red
• Examples of common acids:
  • Hydrochloric acid (HCl)
  • Sulfuric acid (H₂SO₄)
  • Nitric acid (HNO₃)
  • Acetic acid (CH₃COOH)

Bases

• Bases are substances that accept a proton (H+) in a chemical reaction, or donate a hydroxide ion (OH−).
• Common properties of bases include:
  • Bitter taste
  • Slippery feel
  • Ability to neutralize acids
  • Turn red litmus paper blue
• Examples of common bases:
  • Sodium hydroxide (NaOH)
  • Potassium hydroxide (KOH)
  • Ammonia (NH₃)

Salts

• Salts are ionic compounds formed by the reaction of an acid and a base.
• The reaction between an acid and a base is known as neutralization.
  • This reaction produces water and a salt.
• Salts often dissolve in water to form electrically conductive solutions.
• Examples of salts:
  • Sodium chloride (NaCl)
  • Potassium nitrate (KNO₃)
  • Calcium carbonate (CaCO₃)

pH Scale

• The pH scale is used to measure the acidity or basicity of a solution.
• It ranges from 0 to 14.
• A pH of 7 is neutral (e.g., pure water).
• A pH below 7 indicates an acidic solution.
• A pH above 7 indicates a basic solution.

Arrhenius Theory

• The Arrhenius theory defines acids as substances that increase the concentration of H+ ions in water and bases as those that increase the concentration of OH− ions in water.

Brønsted-Lowry Theory

• The Brønsted-Lowry theory defines acids as proton donors and bases as proton acceptors.

Conjugate Acid-Base Pairs

• In a Brønsted-Lowry acid-base reaction, the acid loses a proton to form its conjugate base, and the base gains a proton to form its conjugate acid.

Strong vs. Weak Acids/Bases

• Strong acids and bases completely ionize in water.
• Weak acids and bases only partially ionize in water.

Acid-Base Reactions (Neutralization)

• Acid-base reactions often form water and a salt.
• The reaction of an acid and a base can be used to determine the concentration of an unknown solution using titration techniques.

Importance of Acid-Base Balance

• In living organisms, the maintenance of a precise acid-base balance is critical for proper biological function.
  • Imbalance can lead to various health problems.
• Buffers play an essential role in maintaining pH equilibrium in biological systems.

Amphoteric Substances

• Some substances can act as either an acid or a base, depending on the reaction conditions (e.g., water, amino acids).

Test your knowledge about acids, bases, and salts with this quiz. Explore their properties, reactions, and common examples to understand these fundamental chemical classes better. Ideal for students studying introductory chemistry.