View source for Strong and weak acids

Acids are substances that produce hydronium ions, H<sub>3</sub>O<sup>+</sup>, when dissolved in water.

<b>"Strong"</b> acids ionize completely in water. For example,

[[File:hydroniumion.gif]]

The above reaction indicates that when hydrogen chloride gas reacts with water, hydronium ions are produced in aqueous solution. Note that the arrow points to the products, indicating that virtually ALL the HCl becomes H<sub>3</sub>O<sup>+</sup> and Cl<sup>-</sup> ions in aqueous solution. HCl is therefore a <b>strong acid</b>.

<b>"Weak"</b> acids ionize partially in water.

[[File:vinegar.gif]]

Acetic acid, CH<sub>3</sub>3COOH, does not completely ionize in water. Most of the acetic acid in solution remains un-ionized and a small fraction ionizes to form CH<sub>3</sub>COO<sup>-</sup> and H<sub>3</sub>O<sup>+</sup> ions. To represent this in a chemical equation, a double arrow is used. The longer arrow pointing toward the reactants indicates that acetic acid in solution remains un-ionized. CH<sub>3</sub>COOH is a <b>weak acid</b>. 

==Examples==
Names and formulae of six strong acids. 	
* HCl, hydrochloric acid
* HBr, hydrobromic acid
* HI, hydroiodic acid
* H<sub>2</sub>SO<sub>4</sub>, sulfuric acid
* HNO<sub>3</sub>, nitric acid
* HClO<sub>4</sub>, perchloric acid

Names and formulae of three weak acids.
* H<sub>3</sub>PO<sub>4</sub>, phosphoric acid
* CH<sub>3</sub>COOH, acetic acid
* H<sub>2</sub>CO<sub>3</sub>, carbonic acid


==Content suitability==
BCIT courses:
<span class="pops">[http://www.bcit.ca/study/outlines/chem0011  CHEM 0011]</span>