Acids and Bases

Reactions in water are influenced by whether the solution is acidic, basic or neutral. That is based off the concentration of H+ ions in the solution. An acidic solution has a high concentration of H+ ions. When dissolved in water it releases those H+ ions. Basic solutions release OH- ions when placed in water, creating alkaline solutions.

How basic or acidic a solution is is measure on the pH scale. This scale goes from 1 - 14. Solutions between 1-7 pH are considered acidic. Solutions between 7-14 pH are considered to be basic. A pH of 7 is considered neutral (pure water has a pH of 7). The pH scale is not linear, it's logarithmic (a pH of 6 will have 10 times the H+ ions as a pH of 7).