Question

identify 4 types of chemical reactions that occurred during the Flint water crisis, and give one example of each, specific to the Flint issue.

Answer 1

1) oxidation

Oxidation is Loss of electrons which is shown by metals. In flint river case it is shown by lead and iron

Pb(s) → Pb²⁺(aq) + 2 e^–

2) Reduction: Gain of electrons generally shown by non metals. In river flint due to low pH dissolved oxygen was corroding or oxidizing lead in turn getting reduced. In addition to this, chlorine added to water as disinfectant is also getting reduced.

4 e^– + 2 H₂O (l) + O_{​​​​​​2} (aq) → 4 OH^– (aq)

2 e^– + Cl^{​​​​​}_{​​​​​2} (aq) → 2 Cl^–(aq)

3) Displacement reaction: One metal displaces other.

In order to remove lead from the water system phosphate salts are added which results in insoluble precipitate of lead phosphate. That's why this reaction can also be called precipitation reaction.

Pb^{​​​​​2+} + PO_{​​​​​4}^​3-    →    (Pb₃(PO₄)₂)

4) Neutralization reaction: Acid react with base to produce salt and water. Lead salts such as lead carbonate helps in increasing the pH of the water by consuming H⁺ ions from the water.

CO₃^2– (aq) + H⁺ (aq) → H₂O (l) + CO_{​​​​​2} (g)