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What is the pH scale?

What is the pH scale?

The pH scale is a measure of how acidic or basic a chemical substance is.

  • A pH of 7 is netural
  • A pH less than 7 is acidic 
  • A pH greater than 7 is basic
Strength strong acids weak acids neutral weak bases strong bases
pH 0-2 3-6 7 8-10 11-14
Examples Car acid batteries Lemon juice Water Toothpaste Oven cleaner

Each pH unit changes in strength by a factor of 10.

An acid of pH 1 is 1000 times stronger than an acid of pH 4.

A base of pH 14 is 100 times stronger than a base of pH 12.

The pH is a logarithmic measure of the concentration of hydrogen ions, H+ in solution.

Chemists use the formula pH = -log10[H+] to determine the pH of  a substance.