Inorganic Compounds: Water, Salts, Acids, and Bases

Inorganic Compounds

  • Inorganic compounds include water, salts, and many acids and bases.

Water

  • Most Abundant Inorganic Compound:
    • Accounts for 60%–80% of the volume of living cells.
    • Considered the most important inorganic compound.
Important Properties of Water

  1. High Specific Heat:

    • Ability to absorb and release heat with little temperature change.

  2. High Heat of Vaporization:

    • Evaporation of water requires large amounts of heat.

  3. Universal Solvent:

    • Dissolves and dissociates ionic substances (e.g., Na⁺, Cl⁻).
    • Important for biological processes where ions are involved.

  4. Participates in Chemical Reactions:

    • Necessary for hydrolysis and dehydration synthesis reactions.

  5. Protective Function:

    • Protects certain organs from physical trauma.

Salts

  • Role of Ions:
    • Ions play specialized roles in body functions and are vital for homeostasis.
    • Conduct electrical currents in solution (electrolytes).
  • Examples:
    • Ions involved in muscle and nervous neuron physiology.
    • Calcium and phosphorus are involved in tooth hardness (e.g., NaCl → Na⁺ + Cl⁻).

Acids

  • Definition:
    • Acids dissociate into hydrogen ions (H⁺) and negative ions in water.
    • Considered proton donors.

Bases

  • Definition:
    • Bases dissociate into hydroxide ions (OH⁻) and positive ions when dissolved in water.
    • Considered proton acceptors; they take up H⁺ ions.
    • Important bases in the body include bicarbonate ion and ammonia.

Acid-Base Concentration (pH Scale)

  • pH Scale:

    • pH = 7: Neutral (equal concentrations of H⁺ and OH⁻).
    • pH 7.01–14: Basic (decreasing concentrations of H⁺, increasing concentrations of OH⁻).
    • pH 0–6.99: Acidic (increasing concentrations of H⁺, decreasing concentrations of OH⁻).

  • Examples of pH Values:

    • Neutral: Blood (pH = 7.4), Milk (pH = 6.3–6.6)
    • Acidic: Lemon juice (pH = 2), Hydrochloric acid (pH = 0)
    • Basic: Sodium hydroxide (pH = 14), Household ammonia (pH = 10.5–11.5)

Buffers

  • Importance:
    • Cells are sensitive to slight pH changes, which must be carefully regulated.
  • Function of Buffers:
    • Release hydrogen ions if pH rises too high.
    • Bind hydrogen ions if pH falls too low to maintain homeostasis in acid-base balance.