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ACTIVITY in Solubility, Precipitate, Net Ionic Equation. Last updated May 03, 2023.


In this activity, students will investigate concepts of corrosion and redox as they consider the Flint, Michigan Water Crisis and the question, “How did the lead get into Flint’s drinking water?” As they explore these topics while also considering solubility, students will begin to understand how corrosion control is used to prevent lead from contaminating a drinking water supply.

Grade Level

High School

NGSS Alignment

This activity will help prepare your students to meet the performance expectations in the following standards:

  • HS-ETS1-3: Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs that account for a range of constraints, including cost, safety, reliability, and aesthetics as well as possible social, cultural, and environmental impacts.
  • Scientific and Engineering Practices:
    • Analyzing and Interpreting Data
    • Engaging in Argument from Evidence
    • Obtaining, Evaluating, and Communicating Information


By the end of this activity, students should be able to:

  • Explain the meaning of corrosion and describe how it can be prevented.
  • Compare the reactivity of metals using an activity series.
  • Differentiate between oxidation and reduction.
  • Correctly write both redox and net ionic equations.

Chemistry Topics

This activity supports students’ understanding of:

  • Chemical Reactions
  • Electrochemistry
  • Activity Series
  • Oxidation
  • Reduction
  • Redox Reactions
  • Solutions
  • Solubility
  • Precipitate
  • Net Ionic Equation


Teacher Preparation: 5–10 minutes
Lesson: 90 minutes


  • Student Handout
  • Activity Series of Metals
  • Internet Access


  • No specific safety precautions need to be observed for this activity.

Teacher Notes

  • To learn more about this activity, read the associated article, Exploring Social Justice Through a Chemistry Lens, featured in the May 2023 issue of Chemistry Solutions.
  • This activity is intended to be used as the third part of a semester-long project. Unlike a typical project that is confined to a particular unit or topic, the Flint Water Crisis is used as a focal point of the larger project and is revisited as needed throughout the semester. A variety of chemistry topics and activities are connected to it during this time.
  • Teachers can use this particular activity independent of the larger project or review the related article for more information about the activities that precede and follow this one. In the five-part project, students apply concepts including solution chemistry, stoichiometry, and electrochemistry to the ongoing water crisis in Flint, Michigan. In the process, they also learn about both the science and the societal impact of this issue.
  • Students should have prior knowledge of redox reactions, as well as the concepts of oxidation and reduction. Students will apply their knowledge of these concepts in this activity, as well as net ionic equations and solubility.
  • An Answer Key document is included for teacher reference.

For the Student

Part 1: Corrosion

  1. Watch the Corrosion of Metals video from Fuse School and answer the following questions:
    1. What is corrosion?
    1. What types of compounds form when a metal corrodes?
    1. Why does the nail corrode more quickly than the other objects?
    1. How can a metal be protected from corrosion?
  1. Copper and lead are common metals used for water pipes. Based on your activity series, which is more likely to undergo corrosion?
  1. When corrosion occurs, chemical processes called “oxidation and reduction” or “redox” occur.
    1. Use your notes or the eTextbook (section 22.2) to define oxidation.
    1. What happens to the charge of an atom when it is oxidized? (circle one):

Increases, decreases, remains the same

    1. Use your notes or the eTextbook (section 22.2) to define reduction.
    1. What happens to the charge of an atom when it is reduced?(circle one):

Increases, decreases, remains the same

    1. In the redox reaction happening in lead pipes, lead combines with oxygen to form lead (II) oxide. Write the reaction showing the formation of lead (II) oxide:
    1. What element is being oxidized in the reaction from part e above?
    1. What element is being reduced in the reaction from part e above?

Part 2: Corrosion Control

  1. Orthophosphates, usually in the form of phosphoric acid, can be used as a form of “corrosive control”. However, these compounds were notably missing from Flint’s water. Write a net ionic equation showing how phosphate combines with lead ions.
  1. Consider the solubility values in the table below. Note that not all of them are relevant to this question.

Lead Salt
Solubility (g/100 mL at 20oC)
PbO 0.017
PbCO3 0.00011
Pb3(PO4)2 0.000014
    1. Use the solubility values to explain why the product formed in #4 can protect the inside of pipes from corrosion.
    1. Use the solubility values to explain why the formation of PbO (question 3e above) causes lead to end up in the water supply.
  1. Devise an experiment that would allow us to test the effect of orthophosphates on a metal pipe.