The pH Scale and Cleaning

Eddie Evans on the pH Scale and Cleaning

There are many reasons to understand the pH Scale. I won't go into them, but for below.


The motivation for sharing this blog grew from a conversation I shared with two men who were restoring an apartment after a drug bust. I was explaining that preparing a concrete floor for tile might be done with muriatic acid. I also explained that "neutralizing" the acid after it etched the concrete was important. Hence, the pH Scale came up when I tried to demystify the acid and neutralizer. If anyone is interested in a color coded version of this writing, click here.

If anyone reached this point, I'm impressed by their drive to stay focused in the midst of tedious verbiage. I promise to add more information about cleaning real soon.

The pH Scale is a way to measure the acidity or alkalinity of matter. This idea is all important to professional cleaning. When it comes to decontamination, deactivating, and simply lifting soil from fabrics, knowing about the pH level of a surfactant makes a difference.

If you recall the "number line" from high school algebra, there is a zero (0) in the middle of the line. Every number to the left of this line is a negative number. Every number to the right of this line is a positive number. It's kind of like turning on the hot water (left) to warm the cold water (right) when taking a warm shower. There is a blend of the two opposites, heat and cold to warm.

Well, the same kind of idea works on the pH Scale. Think of the number line's zero. It happens that pure water is like a zero on the pH Scale's number line. The difference is that the number line uses a zero (0) and the pH Scale uses a seven (7) for its middle point. So pure water is a 7 on the pH scale.

So, on the pH Scale, everything to the left of 7 is an acid. Everything on the right of 7 is an alkaline. And pure water exists right between acids and alkaline as a 7. (Did you know that lemon juice is on the acid of the of pH Scale? What side of the pH Scale do you think soda water will be on? What about Clorox Bleach and Dove dishwashing soap?) Where do you think the human body measures on the pH Scale? (stay tuned!)

Just like on the number line, mixing negatives (acids) with positives (alkalizes) will cancel something out.

Get this: If more acid is added to pure water than alkaline, the pure water will become more acidic. If more alkaline is added to pure water than acid, the water will become more alkaline.

If equal parts of acid and alkaline are added to pure water, then we should expect the two to cancel each other out. As a result, our pure water should remain the same on the pH Scale. But, what if the acid material is more powerful than the alkaline, or vice versa? What if we add one gallon of an acid like pure lemon juice to one gallon of pure water? Right, the pure water is now on the acid side of the pH Scale and no longer in the middle.

Now, what if we add one gallon of ocean water to one gallon of pure water? Right, the pure water becomes more alkaline.

And now, what if we add one gallon of pure lemon juice to one gallon of pure water, and then add one gallon of ocean water to this mix? As we might guess, the resulting mixture will be on the acidic side of the pH Scale. This is so because the one gallon of pure lemon juice is much more powerful than the one gallon of alkaline ocean water. What is in ocean water that places it on the alkaline side of the pH Scale? Right, salt. So salt is an alkaline, not an acid. What about pepper, where do you think that it will be found on the pH Scale? Right, on the acid side of the scale.

Again, when we mix a negative, acid, with a positive, alkaline, Acidic and basic are two extremes that describe a chemical property chemicals. Mixing acids and bases can cancel out or neutralize their extreme effects. A substance that is neither acidic nor basic is neutral.

The pH Scale measures how acidic or basic a substance is. The pH Scale ranges from 0 to 14. A pH of 7 is neutral. A pH less than 7 is acidic. A pH greater than 7 is basic, and we may call basic alkaline.

The pH Scale is logarithmic and as a result, each whole pH value below 7 is ten times more acidic than the next higher value. For example, pH 4 is ten times more acidic than pH 5 and 100 times (10 times 10) more acidic than pH 6. The same holds true for pH values above 7, each of which is ten times more alkaline (another way to say basic) than the next lower whole value. For example, pH 10 is ten times more alkaline than pH 9 and 100 times (10 times 10) more alkaline than pH 8.

Pure water is neutral. But when chemicals are mixed with water, the mixture can become either acidic or basic. Examples of acidic substances are vinegar and lemon juice. Lye, milk of magnesia, and ammonia are examples of basic substances.

What is blood's pH level? "The normal pH of human arterial blood is approximately 7.40 [normal range is 7.35-7.45), a weak alkaline solution. Blood that has a pH below 7.35 is acidic, while blood pH above 7.45 is alkaline." (From Wikipedia)