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November 10, 2002
I finally mixed the acid!
We have run into several problems concerning our acid. As it turns out, sulfuric acid, which we chose because of it's common association with acid rain, is a strong acid. This means that it dissociates 100% when reacted. Basically, it is very, very hard to get anything other than a pH of -1 to 1.
Fearing that this would ruin our plants, Tya emailed Bill Green for help. He assisted me in making the acid today.
We mixed 10 mL of the H2SO4 with 1 L of H20 to make our first solution. We believe the pH of that solution to be between -1 and 0. That is VERY acidic. Next we took 10 mL of that solution and mixed it with 1 L of H20. Even though is this a very large ratio of acid to water, we still believe that pH to be somewhere near 1. Bill suggested we use a pH buffer (constant) of 4 for the middle pH.
Bill also suggested that we test nitric acid as well because, according to him, that acid is also showing up in acid rain now because of emissions from cars. So we mixed 10 mL of nitric acid with 1 L of water. I'm not sure what the pH of this will be. We also mixed 10 mL of acetic acid in case we needed another acid to experiment with.
The pH meters in the room didn't have batteries in them, so we didn't get to test the pHs of each solution right away. I was worried that the really strong acids would kill the plants immediately, but Bill said that even the strongest one wouldn't completely kill the plant.
We still plan on using distilled water for the control group, but Bill suggested that we take the pH of it and not assume it to be 7. We decided that regardless of the pH of distilled water, that group will still be the control group since it represents the purest form of water we have available to us.
We'll start treating the plants soon, be sure to stop by and see them!
~Amy