9.3 The Acidic Environment
126.96.36.199 Classify common substances as acidic, basic or neutral
|Acidic |Basic |Neutral |
|Stomach Acid(1-3) |Soaps (10) |Pure water |
|Vinegar (2-3) |Cleaning products (8-14) |Ethanol |
|Citrus fruits (3-5) |Sodium carbonate (washing soda 10) |Table Salt |
188.8.131.52 Identify that indicators such as litmus, phenolphthalein, methyl orange and bromothymol blue can be used to determine the acidic or basic nature of a material over a range, and that the range is identified by change in indicator.
Litmus: A dye that changes colour around the neutral range.
Phenolphthalein: A synthetic indicator that changes colour in the basic range.
Methyl orange: A synthetic indicator that changes colour in the acidic range. Bromothymol blue: A synthetic indicator than changes colour around the neutral range.
Each of the indicators above and a combination of them can be used to determine the acidity/basicity of a substance.
184.108.40.206 identify and describe some everyday uses of indicators including the testing of soil acidity/ basicity
Indicators are used to test pH of soils e.g. barium sulfate. The optimum ph range is needed to grow plants so the pH of soils needs...