Subject: Determination of activation energy for the reaction between bromide and bro

I have done an experiment to determine the activation energy for the 
reaction between bromide and bromate ions.  In this experiment, 10 ml 
of 0.01M phenol and 10 ml of bromide/bromate (V) solution are put 
into a boiling tube,and then 4 drops of methyl red indicators is 
added.
A second boiling tube consist of 5 ml of 0.5M sulfuric acid(H2SO4.
A 1 litre beaker with water is warmed to 75 degree celsius. The two 
boiling tubes are immersed in the water and the content in the two 
boiling are mixed when it reaches the water temperature.  The 
reaction is timed until the methyl red disappears. The experiment is 
repeated at different range of temperature from 65 degree celsius to 
15 degree celsius. 

The rssults that I have obtained showed that the methyl red 
disapeared faster at a higher temperature.

I would like to know:

1. What thermodynamic sign does activation energy (EA) have? What 
does this signify.

2.The reaction did not start until the contents of the boiling tubes 
are mixed,is it because sulfuric acid act as a catalyst in this 
experiment as it lower activation energy between the reactant and the 
products.

3.What is the function of the methyl red in this experiment?

Re: Determination of activation energy for the reaction between bromide and bro