pharmaceutical analysis 1 complete notes of unit 2 included all topics like acid base titration, neutralisation curve, and non aqueous titration

Here we have prepared a completes notes of second unit of  pharmaceutical analysis 1 

This chapter contains some topics of

Acid base titration: 

Theories of acid base indicators, classification of acid base titrations and theory involved in titrations of strong, weak, and very weak acids and bases, neutralization curves 

Non aqueous titration: 

Solvents, acidimetry and alkalimetry titration and

Estimation of Sodium benzoate and Ephedrine HCl

Acid base titration:-

Theories of acid base titration:-

There are two theories of acid base indicator

Ostwald theories:-

1. According to these theories the colour change of any indicator is due to its ionization.

2. An indicator is either weak acid or base, so its ionisation is highly affected in acid and base.

3. If an indicator is  weak acid then its ionisation would be very low in acid due to common hydrogen ion while its fairly ionised in alkali

4. If the indicator is a weak base then its ionisation is large in acid and low in alkali due to common hydroxide ions

5. Phenolphthalein is a weak acid and methyl orange is a weak base

Phenolphthalein:-

• It is colourless, weak acid but after dissociation in water it gives pink colour.

• Under acidic condition, the concentration of anion is less hence it is colourless while in alkaline condition, concentration of the anion is more to produce pink colour.

Methyl orange:-

• It is very weak and can be represented as MeoH

• Methyl orange gives red colour in acidic and in basic medium it remains the same (yellow colour).

Quininoid theories:-

• Acid base indicator exist in two tautomeric form( benzenoid and quinonoid ) having different structure which are in equilibrium

• Colour change of any indicator ia due the structural change of indicator.

• Inter conversion of one tautomer into another tautomer leads to colour change

Eg. Phenolphthalein is benzenoid form in acidic solution and colourless but in alkali solution it is converted into quinonoid form which gives pink colour

Classification of acid base titrations and theory involved in titration of strong, weak, and very weak acids bases:-

Neutralization curve;-

Non aqueous titration:-

Solvents:-

Acidimetry and alkalimetry titration:-

Estimation of Sodium benzoate:-

Estimation of Ephedrine HCl:-