Vernier Software and Technology
Vernier Software & Technology

Acid Rain

Figure from experiment 18 from Biology with Vernier


Acid rain is a topic of much concern in today’s world. As carbon dioxide gas, CO2, dissolves in water droplets of unpolluted air, the following reaction occurs:

{\text{C}}{{\text{O}}_{\text{2}}} + {\text{ }}{{\text{H}}_{\text{2}}}{\text{O}} \leftrightarrow {{\text{H}}_{\text{2}}}{\text{C}}{{\text{O}}_{\text{3}}}

H2CO3 is a weak acid that causes the rain from unpolluted air to be slightly acidic. This source of “acid rain” is not usually considered to be a pollutant, since it is natural and usually does not alter the pH of rain water very much. Oxides of sulfur dissolve in water droplets to cause more serious problems. Sulfur dioxide dissolves to produce sulfurous acid, H2SO3, by the equation:

{\text{S}}{{\text{O}}_{\text{2}}} + {\text{ }}{{\text{H}}_{\text{2}}}{\text{O}} \leftrightarrow {{\text{H}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{3}}}

This source of sulfur dioxide can occur naturally, as from volcanic gases. More often, however, sulfur dioxide is considered a pollutant, since it is a by-product of fossil-fuel combustion.

The acidity of a solution can be expressed using the pH scale, which ranges from 0 to 14. Solutions with a pH above 7 are basic, solutions with pH below 7 are acidic, and a neutral solution has a pH of 7. In Part I of this experiment, you will study how the pH of water changes when CO2 is dissolved in water. In Part II, you will study the effect sulfuric acid has on the pH of different water types.


In this experiment, you will

  • Measure pH.
  • Study the effect of dissolved CO2 on the pH of distilled water.
  • Study the effect on pH of dissolving H2SO4 in various waters.
  • Learn why some bodies of water are more vulnerable to acid rain than others.

Sensors and Equipment

This experiment features the following Vernier sensors and equipment.

Option 1

Option 2

Additional Requirements

You may also need an interface and software for data collection. What do I need for data collection?

Standards Correlations

See all standards correlations for Biology with Vernier »

Biology with Vernier

See other experiments from the lab book.

1Energy in Food
2Limitations on Cell Size: Surface Area to Volume
3Acids and Bases
4Diffusion through Membranes
5Conducting Solutions
6AEnzyme Action: Testing Catalase Activity
6BEnzyme Action: Testing Catalase Activity
8The Effect of Alcohol on Biological Membranes
9Biological Membranes
11ACell Respiration (O2)
11BCell Respiration (CO2)
11CCell Respiration (Pressure)
11DCell Respiration (CO2 and O2)
12ARespiration of Sugars by Yeast
12BSugar Fermentation
13Population Dynamics
14Interdependence of Plants and Animals
15Biodiversity and Ecosystems
16AEffect of Temperature on Respiration
16BEffect of Temperature on Fermentation
17Aerobic Respiration
18Acid Rain
19Dissolved Oxygen in Water
20Watershed Testing
21Physical Profile of a Lake
23AEffect of Temperature on Cold-Blooded Organisms
23BEffect of Temperature on Cold-Blooded Organisms
24ALactase Action
24BLactase Action
25Primary Productivity
26Control of Human Respiration
27Heart Rate and Physical Fitness
28Monitoring EKG
29Ventilation and Heart Rate
30Oxygen Gas and Human Respiration
31APhotosynthesis and Respiration (O2)
31BPhotosynthesis and Respiration (CO2)
31CPhotosynthesis and Respiration (CO2 and O2)

Experiment 18 from Biology with Vernier Lab Book

<em>Biology with Vernier</em> book cover

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