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Turbidity ---> I learnt something new!!!

This may not be a new thing to you, but to me. Turbidity in natural water is due to the presence of finely divided suspended particles of clay, sand or by microscopic organisms. Turbidity is expressed in ppm (parts per million). The standard unit of turbidity is that produced by one part of finely divided silica  in million parts of distilled water. The permissible turbidity limit in water is 5-10 NTU ( Nephelo Turbidity Units).

We did an experiment in our " instrumental methods of analysis lab"
Let me explain what we did.

Estimation of turbidity: 

Aim: To estimate the turbidity of the given solution.

Reagents: Stock Turbidity Solution.

Reagent A :
5 g of hydrazine sulphate is dissolved in 400 ml of distilled water.

Reagent B : 50 g of tetramethyl hexamine is dissolved in 400 ml of distilled water.

The reagents were mixed and made upto 1000ml with distilled water ( 4000 NTU )


We took samples from the stock and prepared solutions of 10, 20, 30, 40, 50 NTU. The turbiditimeter was calibrated with these samples. Blank was distilled water.
The sample we used for finding the turbidity was " Soil particles mixed with water ". Ya, we mixed soil in water purposely for doing the experiment.
We normally do our experiments in groups. our group used soil in water.

Some other interesting and cool samples used by my classmates were : 

Jelly in water ;
Pink color chalk dust in water;
Chocolate in water; ( yum yummy)
silica powder in water;

After calibrating the instrument, soil sample was used and turbidity of the sample we used was found to be 34 NTU.

Why turbidity must be measured ?

In environmental science, Pollution estimation of the water ecosystems is an important one.
Pollution is directly proportional to the turbidity. Hence turbidity is important in this case.

Turbidity of drinking water must be as very low as possible.
Turbid water is not preferred in several cases.
Growth of microbes in broth can also be measured with turbidity of the solution.
Hence , it's important to understand and learn to measure turbidity.

:)))))) veeeeeeeeee......... Happy night after a whole day of study and classes.


  1. as far as my knowledge goes 1NTU = 1mg silica
    (finely divided) in 1 lit water.


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