2P prep 21/09/09

Read pages 78-82 answer questions 1&2....






There are lots of acids and alkalis that we meet in our everyday life, there are also lots which are less common and we see them only in the Chemistry lab.

All acids and alkalis are solutions of compounds dissolved in water. The less water there is the more effective the acid/alkali is in it’s reactions. They both can cause chemical burns but in different ways. Acids tend to dissolve things and leave holes for example if we spill acids on our skin it would leave little holes or dissolve it completely but alkalis would make our skin feel soapy, this is because it is dissolving the layers that hold the skin together.


Both acids and alkalis tend to be clear and colourless liquids, making them hard to tell apart. In fact a lot of liquids are clear and colourless and we need to have a method that will tell us if something is acidic or alkaline or is neither. Something that is neither and acid or an alkali is called a neutral solution. The best way to tell whether a solution is acid or alkali or neutral is using indicator solutions these will change colour depending on the solution. Indicators show the pH of a solution this is a measure of it’s acidity or alkalinity.