C3.3 Types of chemical reaction

• What are redox reactions?

  Redox reactions are chemical reactions involving the transfer of electrons.
• What is the significance of identifying oxidizing and reducing agents in redox reactions?

  Identifying oxidizing and reducing agents helps in understanding the electron transfer process in redox reactions.
• What does the pH scale measure?

  The pH scale measures the acidity or alkalinity of a solution.
• How can you determine the pH of a solution?

  You can determine the pH of a solution using pH indicators or pH meters.
• What are the characteristics of acids and alkalis?

  • Acids: sour taste, turn blue litmus paper red, produce H⁺ ions in solution.
  • Alkalis: bitter taste, turn red litmus paper blue, produce OH^- ions in solution.
• What is the role of indicators in measuring pH?

  Indicators change color at specific pH levels, allowing for the determination of acidity or alkalinity.
• What happens during neutralization reactions?

  Neutralization reactions occur when an acid reacts with a base to produce salt and water.
• How can you predict the salt formed in a neutralization reaction?

  You can predict the salt formed by combining the cation from the base with the anion from the acid.
• What are the products of a neutralization reaction?

  • Salt
  • Water
• What happens when acids react with metals?

  When acids react with metals, hydrogen gas is produced along with a salt.
• What is effervescence in the context of acid reactions?

  Effervescence is the bubbling or fizzing that occurs when a gas is released during a chemical reaction.
• What is the difference between strong acids and weak acids?

  Strong acids completely dissociate in water, while weak acids partially dissociate.
• How does the concentration of hydrogen ions relate to pH?

  The pH of a solution is inversely related to the concentration of hydrogen ions; higher hydrogen ion concentration results in lower pH.
• What is the significance of pH titration curves?

  • Show how pH changes during a titration.
  • Indicate the point of neutralization.
  • Help determine the strength of acids and bases.
• How can you represent a neutralization reaction with a balanced equation?

  A balanced equation for a neutralization reaction includes the reactants (acid and base) and the products (salt and water) with correct stoichiometry.
• What does testing the pH of a solution involve?

  Using an indicator to show colors
• What is the pH range of the pH scale?

  0 to 14
• What defines an acid in terms of pH?

  Substance with pH less than 7
• What ions do acids form in water?

  H+ ions
• What is a neutral substance's pH value?


  pH 7
• What defines a base in terms of pH?

  Substance with pH greater than 7
• What ions do alkalis form in water?

  OH– ions
• What is an alkali?

  A base that dissolves in water
• How is pH related to hydrogen ion concentration?

  Higher H+ concentration means lower pH
• What happens to pH as hydrogen ion concentration increases?

  pH decreases, solution becomes more acidic
• What does the logarithmic nature of the pH scale imply?

  Each pH change is a tenfold change
• What is an acid-base indicator?

  Substance that changes color in solutions
• How does a universal indicator work?

  Changes color with a few drops in solution
• What is the purpose of a pH probe?

  To measure pH electronically
• Why is calibration important when using a pH probe?

  To ensure accurate pH readings
• What is produced during the neutralisation reaction between acids and bases?

  A salt and water
• What is the ionic equation for neutralisation?

  H+ + OH– → H2O
• What is the pH of the products when an acid neutralises a base?

  pH of 7
• How can an indicator show the end of a neutralisation reaction?

  Universal Indicator turns green
• What are titrations used for?

  To determine acid quantity for neutralisation
• What does a titration curve show?

  pH changes with volume during titration
• What is the end-point of a titration?

  The point where solution is neutral
• What is the pH of human skin?

  pH 5.5
• What is the difference between strong and weak acids?

  Strong acids fully dissociate in water
• What does concentration refer to in acids?

  Amount of acid molecules in solution