i) Quantitative Analysis: Gelatinous or very small size particles are difficult to filter and are so difficult to estimate. Such ppt. can be converted into ideal solution (suspension) and then can be estimated by either Nephelometry or Turbidimetry.

ii) The amount of Sulphur present in the coal, Oil, rubber, plastics and several organic materials can be determined. That material which contains sulphur is heated at very high temp so that sulphur present is oxidized to the corresponding SO₄^-2 . This is then treated with BaCl₂ so that suspension of BaSO₄ is obtained. This suspension is then subjected to Nephelometer or Turbidimeter.

iii) Water which is required in power plant (Nuclear Reactor) and steam generating plant (Boiler) must be free from any of the suspended particles that testing can be done by Nephelometer and Turbidimeter. If no response from the instrument it, means water is free from of the suspended impurities.

iv) Air is continuously monitored for dust and other particulate matter using these two methods.

v) Determination of molecular weight of macromolecules i.e. polymer.  Polymers have the property of scattering of light. The turbidity of the solution is related to molecular weight of the polymer. $$ \tau = Hc{ M }_{ w } $$ Where H = constant, depends on polymer and medium.

vi) Turbidimetric Titrations: In this case, the solution of SO₄^-2 is taken in the cuvette and after each addition of the titrant i.e. BaCl₂ the precipitate formation takes place. This ppt, formation goes on increasing till all the SO₄^-2 ions are precipitated and so the turbidance goes on increasing and is maximum at the Equivalence point, after that, it remains constant.

vii) The phenomenon is used in sewage work.

viii) Used in pharmaceutical industries and petroleum refineries.

ix) Used in pulp and paper manufacturing.

x) The phenomenon is applied in the determination of suspended material in liquid found in nature.

i) Quantitative Analysis: Gelatinous or very small size particles are difficult to filter and are so difficult to estimate. Such ppt. can be converted into ideal solution (suspension) and then can be estimated by either Nephelometry or Turbidimetry.

ii) The amount of Sulphur present in the coal, Oil, rubber, plastics and several organic materials can be determined. That material which contains sulphur is heated at very high temp so that sulphur present is oxidized to the corresponding SO₄^-2 . This is then treated with BaCl₂ so that suspension of BaSO₄ is obtained. This suspension is then subjected to Nephelometer or Turbidimeter.

iii) Water which is required in power plant (Nuclear Reactor) and steam generating plant (Boiler) must be free from any of the suspended particles that testing can be done by Nephelometer and Turbidimeter. If no response from the instrument it, means water is free from of the suspended impurities.

iv) Air is continuously monitored for dust and other particulate matter using these two methods.

v) Determination of molecular weight of macromolecules i.e. polymer.  Polymers have the property of scattering of light. The turbidity of the solution is related to molecular weight of the polymer. $$ \tau = Hc{ M }_{ w } $$ Where H = constant, depends on polymer and medium.

vi) Turbidimetric Titrations: In this case, the solution of SO₄^-2 is taken in the cuvette and after each addition of the titrant i.e. BaCl₂ the precipitate formation takes place. This ppt, formation goes on increasing till all the SO₄^-2 ions are precipitated and so the turbidance goes on increasing and is maximum at the Equivalence point, after that, it remains constant.

vii) The phenomenon is used in sewage work.

viii) Used in pharmaceutical industries and petroleum refineries.

ix) Used in pulp and paper manufacturing.

x) The phenomenon is applied in the determination of suspended material in liquid found in nature.

i) Effect of Concentration on Scattering:

The attenuation of a parallel beam of radiation by scattering is given by $$ { I }_{ t }={ I }_{ 0 }{ e }^{ -Jl } $$ $$ \log { \frac { { I }_{ 0 } }{ { I }_{ t } } } =KlC $$ $$where\quad K= \frac { J }{ 2.303C } $$ Where \({ I }_{ 0 }\) and \({ I }_{ t }\) are the intensity of the beam before and after passing through the length \(l\) of a turbid medium. The quantity \(J\) is called turbidity coefficient. Its value is often found to be linearly related to the concentration of the scattering particles. As a consequence, a relationship similar to Beers Law is,

ii) Effect of Particle size on Scattering:

The fraction of radiations scattered at any angle depends upon the size and shape of particles responsible for scattering. Those factors which influence the particle size at the time of precipitation in gravimetric, also affect both turbidimetry and nephelometry. Thus gravimetric factors such as the concentration of reagents, rate, and order of mixing, temperature, pH and Ionic strength are important Experimental variables. For proper scattering see that particles size must be uniform.

iii) Effect of Wavelength on scattering:

It has been shown experimentally that the turbidity Coefficient varies with wavelength as given by the equation \(J=S{ \lambda }^{ -t }\) Where S is Constant for a given system. The quantity t depends on the particle size and has a value of 4 when scattering particles are smaller than the wavelength of the radiations incident on it. For particles with a dimension similar to wavelength, \( \lambda \) is found to be 2. For purpose of analysis ordinary white light is used, but if the solution is colored then we have to select that wavelength so that absorption by the medium is minimum.

i) Effect of Concentration on Scattering:

The attenuation of a parallel beam of radiation by scattering is given by $$ { I }_{ t }={ I }_{ 0 }{ e }^{ -Jl } $$ $$ \log { \frac { { I }_{ 0 } }{ { I }_{ t } } } =KlC $$ $$where\quad K= \frac { J }{ 2.303C } $$ Where \({ I }_{ 0 }\) and \({ I }_{ t }\) are the intensity of the beam before and after passing through the length \(l\) of a turbid medium. The quantity \(J\) is called turbidity coefficient. Its value is often found to be linearly related to the concentration of the scattering particles. As a consequence, a relationship similar to Beers Law is,

ii) Effect of Particle size on Scattering:

The fraction of radiations scattered at any angle depends upon the size and shape of particles responsible for scattering. Those factors which influence the particle size at the time of precipitation in gravimetric, also affect both turbidimetry and nephelometry. Thus gravimetric factors such as the concentration of reagents, rate, and order of mixing, temperature, pH and Ionic strength are important Experimental variables. For proper scattering see that particles size must be uniform.

iii) Effect of Wavelength on scattering:

It has been shown experimentally that the turbidity Coefficient varies with wavelength as given by the equation \(J=S{ \lambda }^{ -t }\) Where S is Constant for a given system. The quantity t depends on the particle size and has a value of 4 when scattering particles are smaller than the wavelength of the radiations incident on it. For particles with a dimension similar to wavelength, \( \lambda \) is found to be 2. For purpose of analysis ordinary white light is used, but if the solution is colored then we have to select that wavelength so that absorption by the medium is minimum.

When the light is incident on a solution containing suspended particles. The fraction of the light it scattered and the remaining is transmitted. If we know the intensity of transmitted radiations then we can have quantitative analysis. This phenomenon is known as Turbidimetry. And if we measure the intensity of scattered radiation then also we can have quantitative analysis, This phenomenon is known as Nephelometry.

When the light is incident on a solution containing suspended particles. The fraction of the light it scattered and the remaining is transmitted. If we know the intensity of transmitted radiations then we can have quantitative analysis. This phenomenon is known as Turbidimetry. And if we measure the intensity of scattered radiation then also we can have quantitative analysis, This phenomenon is known as Nephelometry.

When the light is incident on a solution containing suspended particles. The fraction of the light it scattered and the remaining is transmitted. If we know the intensity of transmitted radiations then we can have quantitative analysis of sample. That phenomenon is known as Turbidimetry.

But if we know intensity of scattered radiations then we can also have quantitative analysis. This phenomenon is Known as Nephelometry.

The scattered radiation is always observed at the angle of either 45°, 90° or at 135° to the incident light.

Turbidimetry and Nephelometry involve the use of Very dilute Solutions Therefore suspended particles must have negligible solubility. Such particles scatter the light considerably and therefore great care must he taken that samples are free of dust particles. The particles of the disperse phase must be very fine so that they do not settle down rapidly.

When the light is incident on a solution containing suspended particles. The fraction of the light it scattered and the remaining is transmitted. If we know the intensity of transmitted radiations then we can have quantitative analysis of sample. That phenomenon is known as Turbidimetry.

But if we know intensity of scattered radiations then we can also have quantitative analysis. This phenomenon is Known as Nephelometry.

The scattered radiation is always observed at the angle of either 45°, 90° or at 135° to the incident light.

Turbidimetry and Nephelometry involve the use of Very dilute Solutions Therefore suspended particles must have negligible solubility. Such particles scatter the light considerably and therefore great care must he taken that samples are free of dust particles. The particles of the disperse phase must be very fine so that they do not settle down rapidly.