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# What is the formula for KF standardization?

What is the formula for KF standardization? How do you calculate Karl Fischer factor? The water equivalence factor F is determined according to the formula 0.1566 x w / v in mgs of H2O per ml of reagent, where W is the sodium tartrate weight in mgs, and V is the reagent volume in ml.

## What is the KF reagent?

Karl Fischer reagent consists of iodine, sulfur dioxide, a base and a solvent, such as alcohol. I2+SO2+3Base+ROH+H2O ⇒ 2Base+HI+Base+HSO4R ······ (1) As described below, this method can be used in both volumetric and coulometric titration systems.

## Why DST is used for 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.

## What is KF factor limit?

Standardization is valid, if concentration should be not less than 5 mg and not more than 7mg. The relative Standard deviation between two average KF factors of water and DST determined consecutively should not be more than 3.0 % [Average of two factors (2 with water and 2 with DST) to be considered for calculation.]

## How do you calculate the factor of Karl Fischer?

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.

## What is the limit of KF factor?

The relative Standard deviation between two average KF factors of water and DST determined consecutively should not be more than 3.0 % [Average of two factors (2 with water and 2 with DST) to be considered for calculation.]

## 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.

## Why is pyridine not used in Karl Fischer titration?

Classic Karl Fisher reagents contained pyridine, a noxious carcinogen, as the base. The reagents most frequently used today are pyridine-free and contain imidazole or primary amines instead.

## 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 pyridine free KF reagent?

An essentially pyridine-free Karl Fischer reagent useful in the determination of water, comprises a dissolving agent containing sulfur dioxide and a pyridine substitute in a Karl Fischer solvent, and a titrating agent containing iodine in a Karl Fischer solvent, wherein the pyridine substitute is an alkali or alkaline …

## What is water content by KF?

The Karl Fischer titration is a moisture determination method specific for water and is suitable for samples with a high water content (titrimetry) and also for those with water content in the ppm range (coulometry).

## What electrode is KF titration?

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 the reaction of Karl Fischer reagent?

What is the Karl Fischer Reaction? The alcohol reacts with sulfur dioxide (SO2) and base to form an intermediate alkylsulfite salt, which is then oxidized by iodine to an alkylsulfate salt. This oxidation reaction consumes water.

## Why is disodium tartrate dihydrate used for KF?

Sodium tartrate dihydrate is the volumetric standard for Karl Fischer titration. Under normal conditions, it is stable and non-hygroscopic. Sodium tartrate dihydrate has a stoichiometric water content of 15.66% and is primarily used for titer determination in volumetry.

## What is anhydrous methanol?

Anhydrous methanol is methanol that is free of water. Methanol is hygroscopic, which means it absorbs moisture, including moisture from the air.

## Why platinum electrode is used in Karl Fischer titration?

Water and iodine are used up in an equimolar ratio. The color change that signals the end point of the reaction is caused by the detection of excess iodine at the double platinum electrode which acts as the indicator, following the consumption of all the water in the sample which leads to the cessation of the reaction.

## What is the difference between loss on drying and water content?

Water content is determined by the Karl Fischer titration method and it consists of only water i.e moisture content. … Loss on drying (LOD) is determined by heating the sample below its melting point in an oven and it includes all volatile matter including water content and solvents.

## What is moisture content formula?

Calculate the moisture content on a wet-weight basis using the following formula: Moisture content (%) = W2 – W3 x 100. W2-W1. where, W1 = weight of container with lid; W2 = weight of container with lid and sample before drying; and W3 = weight of container with lid and sample after drying.

## What is balance calibration?

But what is calibration? In simple terms, calibration is a quantitative comparison. To check the reading of a balance or scale, a reference weight is placed on the pan. The error is defined as the difference between the measured value (the reading) and the true value (the reference weight).

## How do you calibrate a pH meter?

How to calibrate a pH meter

1. Examine the pH electrode. First, check the pH electrode for contamination or damage. …
2. Flush the pH sensor. Next, flush your sensor with distilled water. …
3. Immerse the pH electrode. …
4. Calibrate the pH meter. …
5. Rinse the pH sensor and repeat.

## Why imidazole is used in KF titration?

The use of imidazole instead of pyridine is greatly improving the speed of the KF reaction. … For volumetric KF titration the most often used reagent combination is a one-component reagent titer 5 with dry methanol. One-component reagents contain all the substrates for KF reaction dissolved in a suitable alcohol.

## Is pyridine an acid or base?

Pyridine is weakly basic (pKa=5.2), and is widely used both as a solvent and a catalyst, particularly in condensation, dehalogenation, and acylation reactions 〈43OSC(2)109〉.

## How do you regenerate KF electrodes?

Immerse the diaphragm or the electrode surface in nitric acid, and boil with a hot stirrer. Drain out the chromate inside the cell, and rinse it with pure water for 2 to 3 times until yellowish color disappears. Clean the inner burette with methanol or with alcohol.

## What is the basic principle of titration?

The basic principle of the titration is the following: A solution – a so called titrant or standard solution – is added to sample to be analyzed. The titrant contains a known concentration of a chemical which reacts with the substance to be determined. The titrant is added by means of a burette.

## What is the difference between volumetric and coulometric?

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.