I'm currently removing rust from steel with citric acid dissolved in water. I generally use a wire brush as the final treatment to remove any surface rust that the acid loosened up. The pieces under treatment end up shiny before being painted over for renewed protection.
I haven't found any authoritative answer on this, but online search results seem to recommend soaking the parts in a solution of baking soda as the final treatment after the citric acid. The idea being to neutralize the acid.
What is the purpose of the neutralization step in this scenario? Does it effectively reduce how prone the acid-treated steel is to rusting again?
And assuming the acid actuates on the surface of the steel, would the wire brush treatment be a substitute for the baking soda, if it effectively removes some of the acid-treated metal from the outer layer?
Background: Electrical Engineering. But my Chemistry is indeed very rusty (no pun intended).