Interactive Chemistry Worksheets for Students |
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What are acids and bases?
|
Information |
Acids |
Alkalis (soluble base) |
|
Taste |
Sour |
Bitter |
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Concentrated solutions are |
corrosive – dissolve metals |
caustic – cause burns |
|
Litmus paper |
Turn blue litmus pink |
Turn pink litmus blue |
|
Neutralization |
Neutralize bases to produce salt + water |
Neutralize acids to produce salt + water |
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Formation of ions (charged particles) |
Produce hydrogen ions H+ in water |
Produce hydroxide ions OH- in water. |
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Other reactions |
React with active metals to produce hydrogen. |
React with fats to produce soap. |
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Common uses |
Car batteries, swimming pools, cleaning mortar off bricks and preserving foods by pickling. |
Cleaning products like cloudy ammonia and oven cleaners. |
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Examples |
Sulfuric acid, hydrochloric acid and acetic acid. |
Ammonia and sodium hydroxide |
Acids and bases were first thought as follows. An acid is a substance that tastes sour and a base is a substance that tastes bitter. eg. citric acid tastes sour. Bi-carb of soda tastes bitter or soapy.
Most acids and bases however, are NOT SAFE to taste. eg. Sulfuric acid used in car batteries and caustic soda or sodium hydroxide which is used in oven cleaners.
A strong base is soluble in water and is called an alkali. Alkali solutions are caustic and can cause severe burns. Alkali solutions dissolve fats and are used as cleaning agents. Examples include cleaning products containing cloudy ammonia and oven cleaners which contain caustic soda or sodium hydroxide.
All alkalis are bases however, not all bases are alkalis. Many bases have a low solubility.
| Alkali (strong bases - soluble) | Bases (low solubility) | ||
| Name | Chemical formula | Name | Chemical formula |
| Sodium hydroxide | NaOH | Magnesium hydroxide | Mg(OH)2 |
| Potassium hydroxide | KOH | Calcium hydroxide | Ca(OH)2 |
| Ammonia | NH3 | Aluminum hydroxide | Al(OH)3 |
The oxides of the Group I elements or alkali metals all dissolve in water to produce alkali solutions.
Eg. Sodium oxide + water → sodium hydroxide
Na2O + H2O → 2NaOH
Strong acids are corrosive in nature and dissolve active metals like magnesium, zinc and iron. examples of strong acids include sulfuric acid, hydrochloric acid and nitric acid.
| Name of acid | Chemical formula |
| Hydrochloric acid | HCl |
| Nitric acid | HNO3 |
| Nitrous acid | HNO2 |
| Acetic acid | CH3COOH |
| Sulfuric acid | H2SO4 |
| Sulfurous acid | H2SO3 |
| Carbonic acid | H2CO3 |
| Phosphoric acid | H3PO4 |
Soluble non-metallic oxides dissolve in water to produce acidic solutions.
Eg. Water + carbon dioxide → carbonic acid
H2O + CO2 →H2CO3
What is a chemical indicator?
Chemical indicators are substances that change color in the presence of an acid or base. They can be used to safely determine if a substance is acidic or basic.
Examples of chemical indicators include litmus paper, phenolphthalein, bromothymol blue, methyl red and methyl orange. Litmus is pink in acidic solutions and blue is basic solutions.
The Bromothymol Blues Song
A great Chemistry song by Mark Rosengarten