The words acid, base, and neutral are all familiar. By now in your schooling you have probably learned that water is a neutral substance, lemon juice is an acid, and bleach is a base. You may have been introduced to the pH scale where you learned that water has a pH of 7, while acids have a pH of between 0 and less than 7 and bases have a pH of greater than 7 up to 14. In fact, the pH of lemon juice is around 2.0, while the pH of bleach is around 12.6. Lemon juice is a fairly strong acid, while bleach is a strong base. Your blood has a pH of 7.4, making it slightly basic.
So what exactly makes something an acid or base? Why are some acids and bases stronger than others? Click the image below (or just click here) and read all about the relationship between hydrogen ion (H+) concentration and pH.
Next, watch the video below from Mr. Anderson at Bozeman Science: