Why do we usually use a back titration to determine nickel in steel?

Answer 1

Back titration is often used to determine nickel in steel because nickel can form stable complexes that make direct titration difficult. In a back titration, an excess of a reagent that reacts with nickel is added, and the unreacted excess is then titrated with another solution. This method allows for more accurate measurements by accounting for the complexities of the reaction and the presence of other elements in the steel matrix. Additionally, it minimizes interference from other metals that may be present.