AMPEROMETRIC TITRATIONS

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AMPEROMETRIC TITRATIONS: 

AMPEROMETRIC TITRATIONS

PRINCIPLE The potential applied between polarisable and non-polarisable electode is kept constant and the diffusion current is measured during titration : 

PRINCIPLE The potential applied between polarisable and non- polarisable electode is kept constant and the diffusion current is measured during titration

During the titration , the concentration of the electroreducible ion changes and this change leads to the change in the difusion current . When we plot a graph between diffusion current Vs volume of titrant there is sharp change in the diffusion current , at the end point . The potential applied for the titration is at its limiting value. : 

During the titration , the concentration of the electroreducible ion changes and this change leads to the change in the difusion current . When we plot a graph between diffusion current Vs volume of titrant there is sharp change in the diffusion current , at the end point . The potential applied for the titration is at its limiting value.

eg.., A graph plotted between lead ions titrated with sulphate ions . The first part of curve shows a decrease in diffusion current due to decrease in the concentrtion of lead ions . At the end point the diffusion current leads to a minimum value as the lead ions are removed . The second part of graph shows a straight line which indicates the prescence of sulphate ions which are non-electroreducible .: 

eg .., A graph plotted between lead ions titrated with sulphate ions . The first part of curve shows a decrease in diffusion current due to decrease in the concentrtion of lead ions . At the end point the diffusion current leads to a minimum value as the lead ions are removed . The second part of graph shows a straight line which indicates the prescence of sulphate ions which are non- electroreducible .

Lead Vs Sulphate ions ( reducible Vs non-reducible ions ) : 

Lead Vs Sulphate ions ( reducible Vs non-reducible ions )

Conditions 1.Either the titrate or both should be electroreducible . 2.The potential applied should correspond to the limiting current . : 

Conditions 1.Either the titrate or both should be electroreducible . 2.The potential applied should correspond to the limiting current .

APPARATUS FOR AMPEROMETRIC TITRATIONS The instrument is same as that used in polarography . The : 

APPARATUS FOR AMPEROMETRIC TITRATIONS The instrument is same as that used in polarography . The