Question

Reological Effects of pH The defendant in a lawstait over industrial pollution is accused of releasing effluent of pHI 10 into a trout stream. The plaintiff has asked that the defendant reduce the eftluent's pI to no higher than 7 . The defendant's attorney, aiming to please the court, promises that his client will do even better than that: the defendant will bring the pH of the effluent down to 1! a. Will the defense attorney's suggested remecty be acceptable to the plaintiff? Why or why not? b. What facts about pH does the defense attorney need to understand?

Short answer

No, because pH 1 is too acidic and harmful. The defense should aim for pH 7, which is neutral and safe for aquatic life.

Step-by-step solution

Understand the pH scale

The pH scale is a measure of how acidic or basic a solution is, ranging from 0 (most acidic) to 14 (most basic). A pH of 7 is neutral, meaning it is neither acidic nor basic.

Evaluate Initial and Desired pH Levels

The effluent released is at a pH of 10, which is basic. The plaintiff desires the effluent to be reduced to a pH no higher than 7, which is neutral, not acidic or basic.

Analyze the Attorney's Suggestion

The attorney suggests reducing the effluent's pH to 1, which would make the solution very acidic. This is much stronger than the neutral level requested and could cause additional harm to the environment.

Conclusion on the Acceptability of Suggestion

The attorney's suggestion is not acceptable because reducing the pH to 1 moves the effluent from being too basic to being extremely acidic, potentially causing further environmental damage in the trout stream.

Understanding Required by the Defense Attorney

The defense attorney needs to understand the implications of pH changes. A pH of 1 is too acidic and could damage aquatic life. Bringing the pH to around 7, which is neutral, is the goal as it is safer for the environment.

Key concepts

Understanding Acidic Solutions

Acidic solutions have pH values less than 7. On the pH scale, which ranges from 0 to 14, a lower number indicates a more acidic solution. For example, lemon juice, a common acidic liquid, has a pH of around 2.
Acidic solutions are characterized by an excess of hydrogen ions $H^{+}$. The presence of these ions gives them their corrosive nature, and high acidity can be harmful to both living organisms and materials.

• Acids are found in nature, like in the form of vinegar (acetic acid) or citric acid in citrus fruits.
• The lower the pH value, the stronger the acid, and the more potential harm it can cause if not managed properly.

Understanding these properties is crucial, especially when considering changes to the pH of any given solution in environmental scenarios, such as altering the pH of effluent, which has been the case in this exercise. Lowering the pH of effluent to 1 would make it highly acidic and can prove dangerous to aquatic life.

Neutral pH and Its Importance

A neutral pH is exactly at 7, which is the pH for pure water. This midpoint on the pH scale indicates a balance, where a solution is neither acidic nor basic. This equilibrium is important as it means the presence of equal concentrations of hydrogen ions $H^{+}$ and hydroxide ions $O{H}^{-}$.
Water with a neutral pH is considered a stable environment for most living organisms. This is why, in various environmental and biological contexts, keeping a pH close to 7 is often desirable.

• It supports most aquatic life comfortably, as opposed to extreme pH levels that can be harmful.
• A neutral pH is often the target for effluents discharged into natural water bodies to safeguard the ecosystem.

Achieving a neutral pH benefits ecosystems by maintaining an environment that is more conducive to the survival of plants and animals. This was exactly what the plaintiff in the exercise requested, as effluents with a pH less than 7 (acidic) or greater than 7 (basic) can potentially disrupt the aquatic habitats.

The Environmental Impact of pH

The pH level of a solution can significantly impact the environment, especially aquatic ecosystems. Both extremes of the pH scale can be detrimental. It affects the solubility and biological availability of chemical constituents such as nutrients and heavy metals. For instance, metals tend to be more toxic at lower pH levels.
A pH that's too low (acidic) or too high (basic) can harm organisms:

• Low pH levels can lead to increased solubility of metals, affecting aquatic life.
• High pH levels can harm organisms, leading to problems like reduced oxygen availability.

In the context of the exercise, reducing the effluent pH to 1 can have severe consequences. Such low pH levels could result in the destruction of aquatic habitats, leading to fish kills and reduced biodiversity. Neutralizing the pH of effluents before they are released into natural water bodies is key to minimizing environmental damage.