pH Scale and Acid-Base Reactions

pH Scale

• pH is a measure of the concentration of hydrogen ions (H+) in a solution
• pH scale ranges from 0 to 14
• pH 7 is neutral (neither acidic nor basic)
• pH below 7 is acidic (high concentration of H+ ions)
• pH above 7 is basic (low concentration of H+ ions)
• Each step down the pH scale represents a 10-fold increase in H+ ion concentration
• Each step up the pH scale represents a 10-fold decrease in H+ ion concentration

Acid-Base Reactions

• Acid-base reactions involve the transfer of H+ ions
• Acids donate H+ ions (proton donors)
• Bases accept H+ ions (proton acceptors)
• Types of acid-base reactions:
  • Neutralization: acid + base → salt + water
  • Acid-carbonate reaction: acid + carbonate → salt + water + CO2
  • Acid-metal reaction: acid + metal → salt + hydrogen gas

Strong and Weak Acids

• Strong acids:
  • Completely dissociate in water to produce H+ ions
  • Examples: HCl, HNO3, H2SO4
  • Strong acids are strong electrolytes
• Weak acids:
  • Partially dissociate in water to produce H+ ions
  • Examples: CH3COOH, HF, H2CO3
  • Weak acids are weak electrolytes

Neutralization

• Neutralization is a reaction between an acid and a base to form a salt and water
• General equation: acid + base → salt + water
• Examples:
  • HCl (acid) + NaOH (base) → NaCl (salt) + H2O
  • H2SO4 (acid) + Ca(OH)2 (base) → CaSO4 (salt) + H2O
• Neutralization reactions are exothermic, meaning they release heat

pH Scale

• pH measures the concentration of hydrogen ions (H+) in a solution, ranging from 0 to 14
• pH 7 is neutral, pH below 7 is acidic (high H+ ion concentration), and pH above 7 is basic (low H+ ion concentration)
• Each step down the pH scale represents a 10-fold increase in H+ ion concentration, and each step up represents a 10-fold decrease

Acid-Base Reactions

• Acid-base reactions involve the transfer of H+ ions, with acids donating H+ ions and bases accepting them
• Types of acid-base reactions include:
  • Neutralization: acid + base → salt + water
  • Acid-carbonate reaction: acid + carbonate → salt + water + CO2
  • Acid-metal reaction: acid + metal → salt + hydrogen gas

Strong and Weak Acids

• Strong acids:
  • Completely dissociate in water to produce H+ ions
  • Examples: HCl, HNO3, H2SO4
  • Strong acids are strong electrolytes
• Weak acids:
  • Partially dissociate in water to produce H+ ions
  • Examples: CH3COOH, HF, H2CO3
  • Weak acids are weak electrolytes

Neutralization

• Neutralization is a reaction between an acid and a base to form a salt and water
• General equation: acid + base → salt + water
• Examples:
  • HCl (acid) + NaOH (base) → NaCl (salt) + H2O
  • H2SO4 (acid) + Ca(OH)2 (base) → CaSO4 (salt) + H2O
• Neutralization reactions are exothermic, releasing heat

Test your knowledge of pH scale and acid-base reactions, including concentration of hydrogen ions and acidic/basic solutions.