Question

What is the purpose of an auxiliary complexing agent?

Answer 1

An auxiliary complexing agent is added to an EDTA titration to prevent hydroxide formation. This is added where one of the solutions of titration is a metal cation. This bond between the agent and the metal is important. It must be strong enough to prevent the hydroxide from precipitating but at the same time weak enough to release the cation when EDTA is added. 

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