Acidification
Definition and meaning of Acidification in chemistry.
Acidification is the chemical process of a substance or environment becoming more acidic. It happens when hydrogen ion concentration increases and the overall pH value decreases. This change occurs when acids are added or when base molecules are removed.
In more detail
Acidification can happen through natural cycles or through harmful human pollution. When atmospheric carbon dioxide dissolves in water, it creates a weak carbonic acid. This chemical reaction naturally acidifies regular rainwater and freshwater lake systems.
Ocean acidification is currently a massive global problem for marine ecosystems. Our oceans absorb a huge amount of excess carbon dioxide from the air. This creates millions of tons of new carbonic acid inside the ocean water.
The extra acid drastically lowers the pH level of the entire ocean system. This chemical shift makes it much harder for corals and mollusks to survive. These animals need free carbonate ions to build their hard calcium carbonate shells.
The extra hydrogen ions from the acid steal the carbonate ions away from the animals. Without enough carbonate, their existing shells can actually begin to dissolve into the water. Students often confuse acidification with a liquid becoming a highly dangerous strong acid.
In reality, a tiny drop in pH can cause massive biological damage. The ocean only dropped by a fraction of a pH unit, but the effects are terrible.
Key facts
| Field | General Chemistry |
|---|---|
| Key Mechanism | Increase in hydrogen ion (H+) concentration |
| pH Effect | Always causes the pH value to decrease |
| Primary Natural Cause | Dissolved carbon dioxide forming carbonic acid |
| Relevant Formula | H2CO3 (carbonic acid) |
| Major Environmental Impact | Ocean acidification threatening marine food webs |
Over the last few decades, the average pH of the ocean dropped from 8.2 to 8.1. This might sound like a very small and unimportant numerical change. However, the pH scale is logarithmic, so this represents a huge shift. It actually means there was a twenty-six percent increase in hydrogen ion concentration. This single chemical change threatens every marine animal that grows a protective shell.
Frequently asked questions
What is the main cause of ocean acidification?
The ocean absorbs massive amounts of carbon dioxide gas from the atmosphere. This gas reacts with the ocean water to form a weak acid.
Does acidification mean the ocean is now a strong acid?
No, the ocean is actually slightly basic with a pH around 8.1. Acidification just means the pH is moving downwards closer to the neutral point.
How does acidification affect animals with shells?
The extra acid removes free carbonate ions from the surrounding ocean water. Animals desperately need these specific ions to build and maintain their hard shells.