# Question #0c67e

An ${E}^{0}$-pH diagram, also known as a Pourbaix diagram, is a chart used to record the various stages of an element in different pH levels and voltages.
Here is the ${E}^{0}$-pH diagram for Iron:
This is important for being able to record changes in an element such as Iron. For example, if Iron was in a pH of 2 and received a voltage of -1, it would still remain Iron. However, if the voltage was raised to 1. We can see that Iron has changed its state to $F {e}^{3 +}$.