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I wish I knew what pH is!

You’ve heard about the pH scale by now. Your science teacher must have done at least that that much, if not let Visaya help you out. Of course, most people know about the pH scale and can even name products with lower and higher pH. They’ll tell you acids have pH values lower than seven, bases higher than seven, and pure water the neutral pH of seven.

However, when you ask what it means to have a solution with a pH of three, you won’t get much more than “Acid, right?” So let’s talk about what pH means.


The pH scale is a logarithmic scale that measures the power of hydrogen in a solution. But what does “power of hydrogen” mean? A water molecule has an oxygen atom with a negative polarity and two hydrogen atoms with positive polarity. These three atoms hold hands with a polar covalent bond.

Now let’s imagine two water molecules close to each other. The oxygen atom from one molecule may pull a hydrogen atom from the other molecule. We call this theft the hydrogen bond, and it creates two substances, hydronium and hydroxide.

The pH scale measures the likelihood of this reaction. And on a logarithmic scale, a pH of three has 10 times more hydrogen atoms than a pH of four and 100 times more than a pH of five.

To calculate the pH of a solution you can use this formula:

ph scale
Courtesy of Tes

Okay, these chemical terms can get confusing. Shall we move to the example, then?

We know that pure water has a neutral pH, seven. So in pure water the probability of hydrogen in the solution is one in 10 million (-107). However, in an acid, let’s say one with a pH of two, the probability increases to one in 100 (-102). In bases, the probability drops because of the higher hydroxide concentration. In a pH value of 12, your chance of hydrogen atoms in the solution is one in a trillion (-1012)!

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