Use of Primary and Secondary Titrimetric Standards

Use of Primary and Secondary Titrimetric Standards

Section 1: Defining Titrimetric Standards

  • Titrimetric Standards: Titrimetric standards are substances used to determine the concentration of an analyte during titration. They are often substances of known purity and concentration.
  • Primary Standards: Primary standards are chemicals that are highly pure, stable, have no water of hydration, and have a high molecular weight. They are often used to prepare standard solutions for titrations.
  • Secondary Standards: Secondary standards are substances whose concentration are determined through titration with a primary standard. They may not be stable enough or pure enough to act as primary standards.

Section 2: Utilisation of Primary Standards

  • Stability: Primary standards should be stable in air and not react with the atmosphere, this ensures their purity is maintained over time.
  • Water-Free: The substance must be anhydrous or the water must be part of the formula, omitting uncertainty due to absorbed water.
  • Weight: A primary standard should have a large molar mass to prevent weigh errors, this promotes accurate measurements.

Section 3: Utilisation of Secondary Standards

  • Titration: Secondary standards are used in titrations where the primary standard is impractical to use.
  • Determination: The concentration of a secondary standard is determined by titration against the primary standard.
  • Compared to Primary: Secondary standards are often less stable, less pure and more reactive than primary standards.

Section 4: Choosing Between Primary and Secondary Standards

  • Stability and Purity: Choose primary standards when a highly stable and pure titrative is required.
  • Practicality: Choose secondary standards when primary standards are impractical to use, including instances where the substance to be determined is not readily available as a stable primary standard.

Section 5: Importance in Scientific Analysis

  • Accuracy: The use of primary and secondary titrimetric standards is crucial for achieving accurate results in titrimetric analysis.
  • Application: Understanding these standards and their appropriate usage is necessary for a variety of practical scientific procedures and techniques.