[Farbod]

Hi guys, I hope you are all doing fantastic!

I have recently done a quantitative analysis of aspirin tablets using the calorimetric method. In this experiment, a buffered solution of Iron chloride hexahydrate was used to form a violet complex with the salicylate dianion (formed by heating aspirin with 1M Naoh)

The 0.02M Iron (III) chloride was buffered using HCl-KCL. My question is this. Why is Iron chloride required to be buffered? I have tried to find a source explaining this but after literally hours of searching I found nothing! My assumption is the buffer is to prevent any OH- molecules reacting with the Fecl3(h20)6 to form a hydroxide precipitate. I have also seen this experiment done without the use of such buffer. I am a little confused. If you guys could explain and also provide a source for me to read I would be over the moon.

Thanks! 

[Borek]

I agree it is most likely about hydroxide precipitation, but I have no source for that.