Acid

An acid is more than just a chemical compound; it is a fundamental driver of molecular interactions and industrial processes. Formally, an acid is a substance that, in aqueous solution, increases the concentration of hydronium ions (H3O+) or acts as a proton donor.

To truly understand acids, we must look at three defining theories:

1. Arrhenius Theory: Defines acids by their ability to produce H+ ions in water.
2. Bronsted-Lowry Theory: A broader view where an acid is a proton H+ donor. This is the most practical definition used in engineering.
3. Lewis Theory: The most inclusive definition, identifying an acid as an electron-pair acceptor.

In the manufacturing world, especially in the tube and pipe industry, acids play a vital role in pickling. This process uses strong mineral acids like Hydrochloric Acid (HCl) or Sulfuric Acid (H2SO4) to remove surface oxides (scale) from steel before galvanizing or cold drawing.

We measure the strength of an acid using the pH scale, where a value below 7 indicates acidity.