ACID BASE

• What do titrimetric methods measure?

  Amount of reagent consumed by an analyte
• What is a reagent in titrimetric methods?

  A standard solution of a chemical
• What types of reactions are applied in titrimetric methods?

  Precipitation, acid-base, complexation, redox
• Why are titrimetric methods preferred over gravimetry?

  They offer superior speed and convenience
• What are the types of titrimetry?

  • Gravimetric titrimetry
  • Coulometric titrimetry
  • Volumetric titrimetry
• What is volumetric titrimetry?

  Volume of standard reagent is measured
• What is gravimetric titrimetry?

  Mass of reagent required is measured
• What is coulometric titrimetry?

  Charge in coulombs is measured
• What is the definition of titration?

  Adding standard reagent to analyte solution
• What are the requirements for successful titrations?

  • Reactions must be quantitative
  • Reactions must be fast
  • Suitable means for estimating equivalence point
  • Reactions must be stoichiometric
• What is a standard solution?

  A solution of known concentration
• How is the amount of sample determined in titration?

  By measuring the volume of titrant added
• What are the characteristics of standard solutions?

  • Sufficiently stable concentration
  • React rapidly with analyte
  • React completely with analyte
  • Selective reaction with analyte
• What is the direct method for preparing a standard solution?

  Weighing a primary standard and dissolving it
• What is standardization in titrimetry?

  Titrating a weighed primary standard
• What is a primary standard?

  A highly purified reference compound
• What are the characteristics of primary standards?

  High purity, stability, absence of hydrate water
• What is a secondary standard?

  A titrant standardized against a primary standard
• What is the equivalence point in titration?

  When added reagent equals analyte amount
• What is the endpoint in titration?

  When a physical change indicates equivalence
• What is the formula for titration error?

  Et = Vep – Veq
• How can titration error be minimized?

  By using indicators for endpoint observation
• What are indicators in titration?

  Substances that show observable changes
• What are the types of changes indicators can show?

  • Color appearance or disappearance
  • Change in color
  • Turbidity appearance or disappearance
• What are the characteristics of primary standards?

  • High purity
  • Atmospheric stability
  • Absence of hydrate water
  • Modest cost
  • Reasonable solubility
  • Large molar mass
  • Rapid reaction with analyte
• What are titration curves?

  Plots of concentration-related variable vs. reagent volume
• What are the two types of titration curves?

  • Sigmoidal curve
  • Linear-segment curve
• What is a sigmoidal curve in titration?

  p-function plotted against reagent volume
• What is a linear-segment curve in titration?

  Instrument reading vs. reagent volume
• What is the relationship between titrant and analyte in calculations?

  Mole analyte = mole titrant
• What is normality in titrimetry?

  Number of equivalents per liter of solution
• What is equivalent weight (EW)?

  Weight per equivalent of a substance
• How is equivalent weight calculated for acids?

  EW = FW / # H+ produced
• What is the direct titration method?

  Titrant reacts rapidly with the analyte
• What is the replacement or indirect titration method?

  Preliminary reaction replaces analyte with another
• What is back titration?

  Excess reagent added to analyte, then titrated
• What is the limit of detection in titrimetry?

  Concentration value for detecting equivalence point
• How does accuracy in titrimetry compare to gravimetry?

  Not as good as gravimetric methods
• What are the analytical features of titrimetric methods?

  • Limit of detection
  • Accuracy
  • Selectivity
  • Ease of operation
  • Time efficiency
  • Cost-effectiveness
• What is a titer in titrimetry?

  Relationship between volume of standard solution and analyte