Table of Contents
How do you use a KF titrator?
The principle of Karl Fischer titration is based on the oxidation reaction between iodine and sulphur dioxide. Water reacts with iodine and sulphur dioxide to form sulphur trioxide and hydrogen iodide. An endpoint is reached when all the water is consumed.
What is KF auto titrator?
Karl Fischer titration is a classic titration method in chemical analysis that uses coulometric or volumetric titration to determine trace amounts of water in a sample. It was invented in 1935 by the German chemist Karl Fischer. Today, the titration is done with an automated Karl Fischer titrator.
Which electrode is used in KF titrator?
The most advanced KF titration technology uses a double platinum electrode for electrochemical indication of the end point, but visual and photometric indicators are also used.
What is KF testing?
Karl Fischer (KF) Titration is a technique for the determination of moisture content. It is a process based on the reaction of iodine with water. The KF method is one of the few techniques that will measure water content and not be affected by other volatiles.
What is difference between KF and coulometer?
The main difference between the two is that with the volumetric method, the titrant is added directly to the sample by a burette. Conversely, with the coulometric method, the titrant is generated electrochemically in the titration cell.
What is the principle of KF?
The principle of Karl Fischer’s titration is completely based on the oxidation reaction between sulphur dioxide and iodine. Water reacts with sulphur dioxide and iodine to form hydrogen iodide and sulphur trioxide. When all the water is consumed, it reaches an endpoint.
What is the unit for KF?
Kf is called the molal freezing point depression constant and represents how many degrees the freezing point of the solvent will change when 1.00 mole of a nonvolatile nonionizing (nondissociating) solute dissolves in one kilogram of solvent.
Why DMF is used in KF?
Hydranal-Formamide dry accelerates the speed of KF reaction. Because it can also influence the stoichiometry of the reaction, formamide should not be used at concentrations >50% by volume.
What is KF formula?
Divide the freezing point depression by the molal concentration so you have: Kf = delta Tf / cm. Insert the values for delta Tf and cm. For instance, if you have a solution with a molality of 0.455 which freezes at 3.17 degrees Celsius, then Kf would equal 3.17 divided by 0.455 or 6.96 degrees Celsius.
How do you dilute Karl Fischer reagent?
Place the flask/beaker with sample on a magnetic stirrer. While mixing, withdraw and discard three portions once again. The fourth sample will be injected into the KAM KF unit. From the Main Menu on the KAM KF unit, scroll down to Titration Mode and use RIGHT/LEFT arrows to switch to Dilution Mode indicated by “Dil”.
How do you standardize KF?
Standardization of KF Reagent by Water: Neutralise the solvent with KF reagent. Weigh accurately between 25 to 250mg of water, transfer it into the titration vessel. Titer the content with Karl Fischer reagent to end point to the electrometric or visual endpoint. Perform the above titration in duplicate.
What is KF value?
Kf is called the molal freezing point depression constant and represents how many degrees the freezing point of the solvent will change when 1.00 mole of a nonvolatile nonionizing (nondissociating) solute dissolves in one kilogram of solvent. The table below gives values of Kf for various solvents.