Iodometric Estimation of Copper using Sodium thiosulphate

Determination of Cu(II) using Na2S2O3 with K2Cr2O7 as primary standard
Iodometry
Copper can be estimated iodometrically
Iodometric Titrations: Titrations in which oxidizing agent liberates I2 from an I- solution and then liberated I2 is titrated with a standard solution of reducing agent.
It is an indirect titration
In this titration iodine is liberated by oxidizing agent (Cu2+) which is titrated against reducing agent (sodium thiosulphate solution) using starch as indicator
The reaction between potassium iodide solution and potassium dichromate solution in acidic medium liberates iodine
Sodium thiosulphate (hypo) solution reduces liberated iodine (I2) to iodide (I-)
The reaction between potassium iodide solution and copper sulphate solution liberates iodine
Sodium thiosulphate (hypo) solution reduces liberated iodine to iodide