One of our salesmen asked a researcher about rust.
“I know acid dissolves rust, but I’d like to give customers a more scientific explanation. What should I say?”

Here is my summary of the researcher’s explanation.
Rust removal can be explained by two chemical reactions.

The first is neutralization.
Rust is alkaline.
When rust comes in contact with acid, a chemical reaction occurs between the alkali and acid. This neutralization reaction converts the rust to another substance and this substance is dissolved by rust-removing solution.

The second chemical reaction is redox.
The acid in rust-removing solution reacts with clean, rust-free metal surfaces to generate hydrogen foam.
This redox reaction does not dissolve rust, but it occurs near the rust and helps peel it off.

Thanks to this explanation from the researcher, the salesman is now a little better at explaining rust removal to customers.