7. Test for Soluble Salts
a) Soluble Chlorides
The clay to be tested has to be taken out from the bulk supply by ‘Cone and Quarter’ method - the sample to be prepared is around 1 kg. From this master sample take out about 100 gms and soak it in distilled water about 1 litre. After soaking, stir it for few minutes and leave the sample overnight.
- Pipette out 100ml super natent water and follow the below steps to estimate Chloride.
- Add 5 drops of Phenolphtalein indicator, while the sample turns pink add few drops of Nitric Acid until the pink colour disappears.
- Add 5 drops of Chromate indicator solution
- Titrate the sample solution with Silver Nitrate solution until the colour begins to appear as a faint orange tint.
- Estimate the Chloride based on the Silver Nitrate consumption.
