Litmus tells us if a substance is acidic or basic but not acidic or basic the substance actually is. how The pH scale allows to quantify (put a number) on the acid or base. The pH of a solution can be found using: (i) A pH meter (ii) Universal indicator solution (iii) pH paper (paper soaked in universal indicator solution) pH greater than 7: the substance is alkaline pH less than 7: the substance is acidic pH 7: the substance is neutral Experiment: To investigate the pH of a variety of materials Apparatus: rack of test tubes Chemicals: variety of substances of everyday acids and – see ‘Examples bases’ above Procedure: Put substances in test tubes (they must be dissolved in water if they are not a liquid). Pour in a few drops of universal indicator and shake well (the colour will change according to how acidic or basic the substance is). Use the pH scale to write up results. Universal Indicator pH Scale Acids and Bases part (ii) Common strong acids and bases Acids Bases hydrochloric acid HCl sodium hydroxide NaOH sulfuric acid calcium hydroxide Ca(OH)2 calcium carbonate CaCO3 Sodium hydroxide (caustic soda) is an example of an alkaline substance.
Litmus tells us if a substance is acidic or basic but not how acidic or basic the substance actually is. The pH scale allows to quantify (put a number) on the acid or base. The pH of a solution can be found using: (i) A pH meter (ii) Universal indicator solution (iii) pH paper (paper soaked in universal indicator solution) pH greater than 7: the substance is alkaline pH less than 7: the substance is acidic pH 7: the substance is neutral Experiment: To investigate the pH of a variety of materials Apparatus: rack of test tubes Chemicals: variety of substances – see ‘Examples of everyday acids and bases’ above Procedure: Put substances in test tubes (they must be dissolved in water if they are not a liquid). Pour in a few drops of universal indicator and shake well (the colour will change according to how acidic or basic the substance is). Use the pH scale to write up results. Universal Indicator pH Scale Acids and Bases part (ii) Common strong acids and bases Acids Bases hydrochloric acid HCl sodium hydroxide NaOH sulfuric acid calcium hydroxide Ca(OH)2 calcium carbonate CaCO3 Sodium hydroxide (caustic soda) is an example of an alkaline substance.
4.%20Acids%20and%20Bases.docx