Redox Titrationis Study Materials

Redox titrationis a quantitative determination method whose main reaction is a redox reaction. This reaction can only take place if there is an interaction between compounds/elements/ions which are oxidizing agents and elements/compounds/ions which are reducing agents. So if the standard solution is an oxidizing agent, then the analyte must be a reducing agent or vice versa. Redox titration is widely used in chemical examinations because various organic substances and inorganic substances can be determined in this way. However, for this redox titration to be successful, the following requirements must be met: 1. A suitable pair of redox systems must be available so that stochiometric electron exchange occurs. 2. The redox reaction must proceed quite quickly and take place in a measurable manner (99% perfection). 3. There must be a suitable means of determining the end point. This titration is based onoxidation-reduction reaction between analyte and titrant.Analyte containing the reducing agent is titrated withtitrant in the form of a standard solution of the oxidizer or vice versa. Various redox reaction data are used as a basis for oxidimetric reactions, for example the determination of iron(II) ions, Fe2+in the analyte using a standard solution titrant of cesium(IV), Ce4+ which follows the reaction equation Fe2++ Ce4+ →Fe3++ Ce3+ Oxidation is the removal of one or more electrons from an atom, ion or molecule. Currentlyreduction is the capture of one or more electrons by an atom, ion or molecule. There are no free electrons in a chemical system, and the release of electrons by a chemical substance is always accompanied by the capture of electrons by another part, in other words, an oxidation reaction is always followed by a reduction reaction. Redox titration is widely used to determine levels metals/compounds that act as oxidizing or reducing agents. It seems that it would be impossible to apply redox titration without doing so balancing the reaction Formerly. Apart from that, knowledge about voltaic cell calculations, the properties of oxidizing agents and reducing agents is also very important. With good enough knowledge about all of this, calculating the stoichiometry of redox titrations becomes much easier. Please remember that from balancing the reactions we will get the equivalent value for each compound for calculations The end point of the titration in redox titration can be done by making a titration curve between the solution potential and the titrant volume (potentiometer), or you can also use an indicator. Considering the level of convenience and efficiency, redox titration with indicators is often the one chosen. Some redox titrations use the color of the titrant as an indicator, for example determining oxalate with permanganate, or determining alcohol with potassium dichromate. Redox reactions are widely used in titrimetric analysis for both inorganic and organic substances. Redox reactions can be followed by potential changes, so redox reactions can use potential changes to observe the end point of a titration. Apart from that, a simple method can also be done using an indicator In an oxidation-reduction (redox) reaction, there is a change in the valence of the substances carrying out the reaction. Here the transfer of electrons from the pair occurs reducing to the oxidizing pair. The two half reactions of a redox reaction can generally be written as follows: Red → oks + ne Whereedshows the reduced form (also called reductant or reducing agent),OK sis the oxidized form (oxidant or oxidizing agent),n is the number of electrons transferred andeare electrons. Redox reactions are widely used in the titrimetric analysis of inorganic and organic substances. To determine the end point in a redox titration, it can be done potentiometrically or with the help of an indicator. Volumetric analysis based on redox reactions includes bromatometry, iodometry, iodimetry, iodotometry, permanganometry and serimetry. Potassium permanganate is an inorganic compound with the formula KMnO4. Salt consisting of K+and MnO- 4ion. Potassium permanganate is a strong oxidizing agent that can react in different ways depending on the pH of the solution. Permanganometric titration is used to determine reducing agent levels in dilute sulfuric acid. In the presence of a weak base or acid, a brown precipitate called MnO will form2which is disturbing. a. In dilute sulfuric acid: MnO-+ 8 H++ 5 e→M N2b. In weak acids: 4 + 4 H2O MnO- 4+ 4 H++ 5 e→MnO2+ 2 H2O c. In neutral or basic solutions: MnO- 4+ 2 H2O + 3 e→MnO2+ 4 OH– In principle, permanganometric titration is carried out with the help of heating (± 70°C) to speed up the reaction. At the beginning of the titration reaction, the red color remains steady for a few moments, indicating that the reaction is slow. 2 KMnO4+ 3 H2SO4→ K2SO4+ 2 MnSO4+ 3 H2O+O2 When the next titrant is added, the red color disappears more quickly because the Manganese (II) ion that occurs functions to speed up the reaction. Next, the titrant can be added more quickly until the end point is reached, namely arriving at a drop where the pale pink color remains stable. The end of the titration is marked by the appearance of a pink color caused by excess permanganate. Permanganometric titration does not require an indicator because it is a KMnO solution4itself already functions as an indicator (autoindicator). This reaction is slow at room temperature and usually requires heating to 60ºC. Even at higher temperatures the reaction will run slower and faster after the formation of manganese (II) ions. When additional titration droplets are added, the red color disappears more quickly because the manganese (II) ion that occurs functions as a catalyst, a catalyst to speed up the reaction. Sources of error in permanganometric titrations include: KMnO solution4on the burette. If the experiment is carried out for a long time, the KMnO solution4When the burette is exposed to light, it decomposes into MnO2so that at the end point of the titration a brown precipitate will be formed which should be a rose colored solution. Addition of KMnO4which is too fast in the H solution2C2O4to which H has been added 2SO4 and has been heated is likely to cause a reaction between MnO- 4with Mn2+. MnO4-+ 3 Mn2++ 2 H2O ↔ 5 MnO2+ 4 H+ Addition of KMnO4which is too slow in H solution2C2O4to which H has been added2SO4and if it has been heated, there may be a loss of oxalate because it forms peroxide which then decomposes into water. H2C2O4+ O2↔ H2O2+ 2 CO2↑ H2O2 ↔ H2O+O2↑ This can cause a reduction in the amount of KMnO4required for the titration which will ultimately result in an error in the permanganometric titration being carried ou