Hey, I have done all the varying concentrations for the experiment and am writing a report at the moment but one thing Im not too sure on is why the reastion has to take place with a dilute acid - Sulphuric Acid - and why does it affect the reaction. Im really not sure, please help?
Sian x

Hey, I have done all the varying concentrations for the experiment and am writing a report at the moment but one thing Im not too sure on is why the reastion has to take place with a dilute acid - Sulphuric Acid - and why does it affect the reaction. Im really not sure, please help??
sian x
Google will point you to many web sites that describe the reactions, Wikipeida (http://en.wikipedia.org/wiki/Iodine_clock_reaction) being an example. There are several ways to do this experiment, so find one that fits yours.

In one example, the first step is H2O2 + 3 I- + 2 H+ --> I3- + 2 H2O, thus H+, such as sulfuric acid, is required. Since it is a slow, rate-determining step, the concentration of H+ affects the overall rate of reaction.

When using the Web, I advise finding several sites and compare, don't just trust one. :D