AcidRain

Intro

Acid rain is a common problem in the United States because many mechanical/industrial processes produce non-metal oxide gases, for example CO₂. These gases combine with the water in the atmosphere to produce acids which then fall to the ground as acid rain. The acid ends up in lakes and kills the aquatic life; it also is harmful to plant life on land.

Different types of pollution are more harmful because they produce stronger acids; these strong acids tend to be more potent and their impact on nature is more easily seen. The pH of the acid rain depends upon how much this acid dissociates (breaks up). Stronger acids break up into their respective ions more and have lower pHs. The pH is lower because the stronger acid will yield a higher concentration of H+ per the same amount of gas added.

Pre-Lab/handy stuff

• pH probes (at least the one we used) aren't always reliable. Before using a probe, check its reading against a standardized buffer solution to get optimal results (ask teacher for a 4,7,or 10 pH solution). For example our probe read the 4.00 pH buffer solution as having a pH of 4.40. Adjust any calculations accordingly.
• If no Beral pipets are availible to mix the solid in, cut the stem of a Transfer pipet somewhere between the .5 and .75 mL mark. Any longer will not work. The 15 cm Beral pipet will be needed to bubble the gas through the water because Transfer pipets won't fit in a test tube with the pH probe in it.
• The lab has you do this experiment with the same process for each different chemical at the same time. This seems counterproductive as the gas may escape while you are prepairing the other pipets. Instead do the entire lab using one solid at a time.
• When you mix the HCl and NaNO₂ it bubbles a lot so try not to get it on your skin because it burns.
• We couldn't get the NaHSO₃ to produce enough gas to change the pH of the H₂O. You can still try it but don't be surprised if it doesn't work.