What is water content by KF?
What is water content by KF?
KF has a high accuracy and precision, typically within 1% of available water, e.g. 3.00% appears as 2.97–3.03%. Although KF is a destructive analysis, the sample quantity is small and is typically limited by the accuracy of weighing.
What electrode is KF titration?
double platinum electrode
Why is DST used in KF calibration?
DST is primary standard and it is stable up to 150 degree Centigrade. It release free water molecules easily when reacts with KF reagent. This DST has 15.66% water molecules so we can easily calculate and standardize the KF reagent. We use the factorof DST the compound which has less than 1% of moisture.
What is the formula for KF standardization?
6.4 The standardization is accepted when two determinations agree within 0.5% relative. 6.5 The factor F (mg H2O/ml KF reagent´) is calculated as: ; ; Page 2 a = g sodium tartrate dihydrate ml = ml KF reagent. 6.6 Choose titrant and solvent based on the standardization 6.
How do you calibrate KF?
Weigh accurately about 0.005 to 0.05 gm (5 to 50 mg) of water with the syringe and enter the weight in gram. 5. Press the “RUN” key so that red light will glow on “BUSY” position. Again press the “RUN” key so titration will starts.
How do you calculate water content in KF?
The water equivalence factor F, in mgs of H2O per ml of reagent, is calculated according to the formula 0.1566 x w/v, where W is the weight in mgs of sodium tartrate and V is the volume in ml of the reagent.
Why only methanol is used in KF titration?
Methanol is typically used as the working medium in the titration cell. Two- component reagents have better long-term stability and faster titration times than one- component reagents, but are usually more costly, and have lower solvent capacity.
How many types of titration are there?
Such titrations, classified according to the nature of the chemical reaction occurring between the sample and titrant, include: acid-base titrations, precipitation titrations, complex-formation titrations, and oxidation-reduction (redox) titrations.
What is Karl Fischer principle and reaction describe it?
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.
Why imidazole is used in Karl Fischer?
Heterocyclic amines, such as imidazole usually show weakly alkaline properties. Water determination can thus be carried out according to standard methods. Imidazole is the most widely used base for the production of Karl Fischer reagents.
What is the use of Karl Fischer?
Karl Fischer (KF) titration is a redox reaction which uses the consumption of water during the reaction to measure the amount of water in a sample. It is the reference method for water determination because of its specificity, accuracy and speed of measurement. It takes place in an organic solvent.
What are major differences between volumetric and coulometric titration?
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. The coulometric method measures water levels much lower than the volumetric method.
What is difference between volumetric and conductometric titration?
Volumetric titration does not give correct endpoint for polybasic acids, while conductometric titration can be conveniently used in such cases. Conductometric titration can be used where there is no appropriate pointer.
Why coulometric titration is more sensitive than volumetric titration?
Reagent type It is known as an absolute method. The coulometric cell contains two compartments, an anode and a cathode. It is extremely sensitive to the presence of water and therefore the cell must be impervious to any moisture from outside. Pre-titration is therefore a lengthier process in coulometric KF titration.
Why does pH increase suddenly after adding NaOH?
Solid NaOH consists of Na+ and OH- ions packed into a crystalline lattice. When this solid is added to water, the ions float apart leading to extra OH- ions in the water: NaOH → OH- + Na+. The resulting large concentration of OH- makes the solution more basic and leads to a dramatic increase in the pH.
Is titration a colorimetric?
Titration is a kind of volumetric measurement, whereby you measure the unknown indirectly by adding another chemical or reagent that will react with it to make a visible change. This approach is called colorimetric titration because you measure your progress through the use of a change in color.
Why colorimetric analysis is done?
Colorimetric analysis is the technique normally used to determine the concentration of analyte through comparing the color changes of the solution.