Non aqueous titration

Non aqueous titration

1. Non-Aqueous Titration AYESHA SHAFI

2. contents What is non-aqueous titration. Theory and role of solvents. What is non-aqueous solvents it's types. Aprotic solvent Protogenic solvent Protophillic solvent Amphiprotic solvent. Detection of end point. Non-aqueous Indicators.

3. WHAT IS NON AQUEOUS Titration? Non aqueous titration are those titration in which titration of weak acidic or basic substance carried out using non aqueous substance.so has to get end point . Such titration can also be used for the titration of those substance which are not soluble in aqueous solvent. It provide a solvent in which organic compound are soluble. Non aqueous solvent are basically used for those acid or base (1) Which don’t give sharp end point in titration. (2) Which don’t soluble in water. Hence non aqueous titration is a titration of substance which dissolve in non aqueous solvent and it is suitable for weak acid and weak base.

4. Theory and role of solvent The role of solvent in making a substance and strongly weak acid and strongly weak base. Ex:-Like HCL in water is strong acidic. HCL in water is weak acidic. Acetic acid in water is weakly acidic where as acetic acid in ammonia is strongly acidic thus the acidic or basic character are depend on the uses of appropriate solvent . The non aqueous titration can be explained by the use of Bronsted -Lowry theory. According to this theory an acid is a proton donor and base is a proton acceptor .

5. What is non-aqueous solvent & it's types Non aqueous solvent which are used in non aqueous titration are called non aqueous solvent. They are following types:- Aprotic Solvent Protogenic Solvent Protophillic Solvent Amphiprotic Solvent

6. Aprotic solvent Aprotic solvent are most important solvent in this titration. This solvent are chemically inert and they work as a catalyst. Like this solvent are increase the rate of speed in reaction and also decrease the rate of speed in reaction during the chemical process or reaction it will depend on condition. The most important examples of aprotic solvent are Chloroform Benzene

7. 2. Protogenic solvent Protogenic solvent are acidic in nature. And they can donate the proton, and they enhance the strength of weak bases. Examples of Protogenic solvent are HCL H2so4

8. 3.Protophillic solvent Protophillic solvent are basic in nature. Which possess a high affinity for proton. Examples:-Liquid ammonia, amines and ketone.

9. 4.Amphiprotic Solvent Amphiprotic solvent are those solvent they work as a both mean Protogenic or Protophillic. It means Amphiprotic solvent are acidic and basic in nature. And they are accept the proton and donate the proton . For examples:- Water, Alcohols and weak organic acids

10. Detection of end point Visual indicator are formed to the most suitable for the detection of end point in non-aqueous titration . The important indicator used for non-aqueous titration are follow:- Crystal voilet:- It is used as 0.5% solution in glacial acetic acid, it gives voilet colour in basic medium and yellowish green in acidic medium. It is most widely use for the titration of pyridine with prechloride acid. Oracet Blue B Indicator:- It is prepared o.5% glacial acetic acid. It gives blue colour in basic medium while pink colour in acidic medium . Quinaldine Red Indicator:- It is used 0.1% solution in methanol/ethanol . Methanol is more stable. It gives yellow colour in basic medium while almost colourless in acidic medium . a

11. Indicator method: Crystal violet (0.5 per cent in glacial acetic acid) violet blue-green yellowish-green α- Naphtholbenzein (0.2 per cent in glacial acetic acid) blue or blue-green orange dark-green Oracet Blue B (0.5 per cent in glacial acetic acid) blue purple pink Quinaldine Red (0.1 per cent in methanol) magenta ------- almost colour less Indictor Basic Neutral Acidic Color changes Thymol Blue yellow blue

12. ADVANTAGES OF NON AQUEOUS TITRATIONS 1) Organic acids and bases that are insoluble in water are soluble in non-aqueous solvent. 2) Organic acid, which is of comparable strength to water, can be titrated easily in non-aqueous solvent. Bases also follow the same rules. 3) A non-aqueous solvent may help two are more acids in mixture. The individual acid can give separate end point in different solvent. 4) By the proper choice of the solvents or indicator, the biological ingredients of a substance whether acidic or basic can be selectively titrated.

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