PC3 M7

• REDUCTION

  • GAIN of electron/s during a chemical reaction and loss of oxygen
  • DECREASE in oxidation state/number

  RIG - Reduction is GAIN of e-

  • GEORA
• OXIDATION

  • LOSS of electron/s during a chemical reaction and a gain in oxygen
  • INCREASE in oxidation state number

  OIL - Oxidation is LOSS of e-

  • LEORA
• LEORA

  • Loss Electron Oxidation Reducing Agent
• GEROA

  • Gain Electron Reduction Oxidizing Agent
• FARADAY'S LAW

  • A change in charge of one is equivalent to the gain or loss of 96,500 C of electricity for each formula weight of element or group of elements involved.
  • One gram of hydrogen, acting as a reducing agent, loses electrons equivalent to 96,500 C. Therefore, the equivalent weight of a reducing agent is that weight which loses electrons equivalent to 96,500
• A combination of oxidizing and reducing agents results in a reaction that may be used as the basis for the quantitative measurement of one of the reactants.
• The amount of reducing agent or oxidizing agent in the sample can be

  determined by measuring a chemically equivalent amount of oxidizing agent or reducing agent, respectively.
• PERMANGANOMETRY Also known as "Permanganate Titration"
• DIRECT PERMANGANOMETRY

  Assay: Hydrogen Peroxide

  • Although H2O2 generally acts as an oxidizing agent and is reduced to H2O, in this assay it reduces the potassium permanganate while it is being oxidized to oxygen, O2.
  • To comply with the USP definition, a solution of H2O2 should contain NLT 2.5 g and NMT 3.5 g of H2O2 per
• When oxygen gas unites with hydrogen gas forming water, the oxygen is reduced and the hydrogen is oxidized.
• When carbon burns in the presence of oxygen to form carbon dioxide, the oxygen is reduced and the carbon is oxidized.
• RESIDUAL PERMANGANOMETRY

  Assay: Manganese Dioxide (Precipitated)

  BLANK TITRATION: An OA (MnO2) can be determined indirectly with another OA (KMnO4) by measuring the amount of unreacted H2O2 in the sample as compared with that found in the blank.

  • The difference represents the equivalent amount of MnO2 in the sample.
• CERIMETRY (Cerric Sulfate Titration)
• Ce(SO4)2 + dil H2SO4

  • It is a strong oxidizing agent and is more stable than standard permanganate solutions, provided sufficient H2SO4 is present to prevent hydrolysis and precipitation of basic salts.
  • Although permanganate can be reduced to any of the several oxidation states, Ce3+ always results in a reduction of Ce4+.
• Orthophenanthroline + FeSO4 Soln

  It dissolves readily in aqueous solutions of ferrous salts, 3 molecules combining with one ferrous ion to form complex ions, known as ferroin, having an intensely red color.
• • Strong oxidizing agents convert the ferrous to ferric complex, which has a slight blue color, the intensity of which is much less than that of the ferrous complex so it functions as a one-color indicator.
  • The color change (RED to BLUE) is reversed by reducing agents. The blue oxidized form is very stable to be further changed by strong oxidizing agents.
• Iodometry

  • we determine the concentration of the oxidizing agent in a given sample solution using an indirect method.
• Iodometry

  • an indirect procedure where the sample (which is an oxidizing agent) is reduced with excess potassium iodide and an equivalent amount of iodine is produced.
• Iodometry

  STANDARD SOLUTION: Sodium Thiosulfate

  INDICATOR: Starch

  END POINT: Change in color from blue to colorless solution
• IODOMETRY

  For analysis of OXIDIZING agent

  Titrating Soln: Standard Sodium Thiosulfate Solution

  Endpoint: Disappearance of blue color

  Indirect Method of Titration

  Indicator: Starch
• IODIMETRY

  For analysis of REDUCING agent

  Titrating Soln: Standard lodine Solution

  Endpoint: Appearance of blue color

  Direct Method of Titration

  Indicator: Starch
• lodometry

  • The quantitative analysis of a solution of an oxidizing agent by adding an iodide that reacts to form iodine which is then titrated.
• lodimetry

  • A volumetric analysis Involving either duration with a standardized solution of lodine or the release by a substance under examination of iodine in soluble form so that we can determine its concentration by titration.
• lodometry (Principle)

  • lodides react with another oxidizing agent in an acidic medium or neutral medium.
• lodimetry (Principle)

  • Uses free iodine to undergo titration with a reducing agent.
• Iodimetry


  The concentration of the reducing agent in a given sample solution is determined by titrating it against a standard iodine solution using direct method
• Iodine solubility (lodimetry)

  1. Iodine is made soluble by dissolving it with KI

  2. The triiodide ion is more soluble in water
• Titration (lodimetry)

  The reducing agent reduces all iodine from the triiodide solution to iodide ion
• Endpoint (lodimetry)

  • Without an indicator, the endpoint is achieved gradually
  • It is advised to use an indicator for a rapid change in color