Why does soda fizz?
It happens because Henry’s law states that it would happen.
Hey! I want to know why soda produces those bubbles when I open a bottle containing soda, and not about Henry’s law!
Okay! Let’s see it this way: soda is, chemically speaking, nothing but carbon dioxide gas dissolved in water. Occasionally, salts such as sodium bicarbonate, are added to this solution of carbon dioxide and water to reduce its acidity.
My question is still not answered!
To understand, what happens when a soda bottle is opened, we just need to have a quick look at Henry’s Law. He stated: “At a constant temperature, the amount of a given gas dissolved in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid.”
I’m all topsy-turvy!
You know a gas exerts pressure on everything. And when filling the soda into bottles some gas is also forced into them with the help of high pressure amounting to a few hundred atmospheres. And Henry’s law states that high pressure along with low temperature of a liquid is a good thing if we want to dissolve a lot of gas into a given amount of the liquid. Factories making sodas make use of this principle and dissolve a lot of gas into bottles of soda.
But, when the same bottle comes into our hands, it is no longer in the freezer at a low temperature. And, when we remove the bottle cap of the soda bottle, the pressure on the soda inside it reduces to just one atmosphere. Because these conditions are not favorable for a liquid that has got a lot of gas dissolved in it, the already dissolved gas starts to come out. And when the gas begins to come out, the surface of the soda begins to bubble and we see our familiar soda fizz!
Category: Science