Karl Fischer Titration: Overview, Questions, Preparation

Water responds with iodine and sulfur dioxide to form sulfur trioxide and hydrogen iodide. An endpoint arrives when all the water is burned through. The synthetic condition for the response between sulfur dioxide, iodine, and water (which is utilised during Karl Fischer titration) is given below:

I2 + SO2 + H2O → 2HI + SO3

Karl Fischer Titration Equipments

Drying tube, test infusion cap, terminal investigation, drain cook, a cathode chamber, identification cathode, rotor, anode chamber, KF reagent. 

Elements of KF Reagent

Iodine, buffer (imidazole), sulfur dioxide, dissolvable (methanol).

Procedure

The Karl Fischer titration trial can be performed in two ways. They are: 

• Volumetric assurance – This method is appropriate to decide the water content down to 1%. The example is disintegrated in KF methanol, and the iodine is added to KF reagent. The endpoint is recognised potentiometrically. 

• Coulometric assurance – The endpoint is identified in this examination electrochemically. Iodine needed for KF response is acquired by anodic oxidation of iodide from the arrangement.

Applications

• It is used in specialised items, for example, plastics, oils, gases

• It is used in drug items

• It is used in restorative items

• It is used in the business

Advantages

• It is fitted for deciding water percentage in gases, fluids, and solids. 

• The coulometric titrator helps in distinguishing free water, broken down water, and emulsified water. 

• It is a quick cycle that requests an insignificant measure of test arrangement. 

Limitations

• Coulometric titration is fitted just for tests that contain a decent quantity of water. 

• Coulometric titration takes incredibly significant stretches to decide.

Karl Fischer Titration in Class 11 

In class 11, Karl Fischer titration has been discussed in the chapter of Redox Reaction, where titration is the major part and has been discussed thoroughly with the reactions and the way to perform it. The chapter has a weightage of 20 marks in the exam. 

Illustrative Examples

• What is the use of Sodium tartrate in Karl Fischer?

The volumetric norm for Karl Fischer titration is sodium tartrate dihydrate. It is steady and non-hygroscopic, under typical conditions. Sodium tartrate dihydrate has a 15.66% stoichiometric water content and is principally utilised in volumetry to gauge the titer.

• How can we make Karl Fischer reagent?

A dissolvable liquor (ROH), a setup grouping of iodine (I2), a base (RN), and sulfur dioxide (SO2) are the reagents. In a fluid climate, the Bunsen response among iodine and sulfur dioxide is the reason for the responses of Karl Fischer reagents.

• Define Volumetric Karl Fischer.

The Karl Fischer titration is simply a method for estimating the water content. Current instruments, for example, the Aquamax KF, apply the coulometric rule, whereby the water present in the example is volumetrically titrated to a predefined endpoint at which free iodine surpasses a moment.

Q. What is the use of methanol in this process?

Q. How can we calculate the Karl Fischer factor?

Q. What is the working principle of Karl Fischer titration?

Q. What material can be used as moisture protection in the procedure?

Q. Through which method can we determine the water content in titration?