How Does pH Affect Enzyme Activity in Starch-Iodine Reactions?

[originalr]

I did an experiment and i AM A FIRST YEAR STUDENT AND I NEED HELP EXPLAINING WHAT TOOK PLACE. I ADDED 1% STARCH TO THREE TEST TUBES AND THEN 1 DROP IODINE. THEN IN ONE THE TUBE I ADDED 3 DROPS OF 1M NaCl AND then to another i added 3 drops 1M HCl and then i added to the last one i added 3 drops of water. i observed that the solution with NaCl took 75 sec to turn colourless or clear , THE SOLUTION WITH 1M HCl never changed and the solution with water took 180 second to turn colorless...How do i explain what really happen.

 

[Kalirren]

You're already explained what -happened- just fine.

What happened to the enzyme in each test tube?

Also, this should be in the homework forum.

 

[Borek]

And no need to shout.