Analytical Determinations Using Faradays Law

The accuracy is as good as gravimetric methods and coulometry is much faster than gravimetry and classical volumetric methods of analysis. 

The relationship between charge and amount of analyte for a constant current, i, can be stated as 

This relationship involves only fundamental quantities there are no empirically determined calibration factors, so standardization and calibration are not required. This makes coulometry an absolute method it does not require calibration with external standards. The current efQciency must be 100%. For a variable current, the charge is given by 

A sample of stannic chloride was rednced completely to stannous chloride according to the reaction Sn + 2e — Sn.  

The applied current was 9.65 A and the time taken for reduction was 16.0 min 40 s. What was the initial weight of stannic ion present First convert the time to seconds. 16.0 min X 60 s/min = 960 s. Adding the additional 40 s gives a total time of 1.00 X ICP s  

---