Balancing pH

Lesson Plan - Get It!

Audio:

In the previous lesson of our All About pH series, found under Related Lessons in the right-hand sidebar, you learned about acids and bases.

We also talked about neutral solutions, which have a pH value close to 7. Remember that all solutions can be classified by the level of acidity along the pH scale.

There are some substances that need to maintain a constant pH all the time.

• Can you think of some examples of solutions that should not change pH value?
• What about blood and drinking water?
• What do you think would happen if blood became too basic?

Discuss your responses with a parent or teacher.

We know that acids and bases can harm our bodies, so it is very important that blood keeps a constant pH. To help solutions maintain constant pH values, we can use buffers. Buffers are substances that help keep pH values stable or constant. They work in the same way as the blue tires in the beginning of the lesson, keeping pH from changing too much and going outside of the boundaries.

Buffers can work to keep neutral substances at a pH of 7, as well as operate on acids and bases to keep them stable. For example, there are buffers that keep strong bases high on the pH scale.

• How do these buffers work?

Well, remember that we learned about hydrogen and hydroxide ions acting to create acids and bases. Substances with high hydrogen ion concentration are acids and high hydroxide ions are bases. Buffers work by adding hydrogen or hydroxide ions to balance out materials that may be in the environment. They add these ions to ensure minimal changes in pH.

_{Image by Uopchem25moffet, via Wikimedia Commons, is licensed under the CC BY-SA 3.0 license.}

Analyze the image above.

• What does it tell you about how buffers react to solutions?
• Notice how either hydroxide (OH) or hydrogen (H) ions are replaced or added; how do you think these ions impact the overall pH?

Buffers serve an incredibly important role in the body, ensuring that fluids maintain an appropriate pH value.

• Why do you think this is so important?
• What processes in your body could be disrupted by changes in pH?
• How do buffers work to keep pH constant?

Discuss the answers to these questions with a parent or teacher before moving on to the Got It? section, where you will learn more about buffers.