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Neutralisation of Distilled Water.



Distilled water can be used to dilute a sample to -

• to increase the working volume -
  
  
  • to accommodate the stirrer bead
    
  • to accommadate a pH electrode assembly
    
  • to obtain a volume that can more easily be stirred manually (see diagram)
    
    
• to dilute red wine colour which can cause interference with a colour indicator used to detect the end point
  
  
• To collect a volatile acidity distilate.
  
  
  Note:even distilled/deionise water can be slightly acidic due to the presence of carbon dioxide (CO₂ ) existing as as carbonic acid in solution.
  
  This is indicated by pink colouration in the presence of a pH indicator such as phenolpthtalien as indicated by the pink hue.
  
  Hence distilled/de-ionised water will require neutralization.
  
  
  

1. - Pour approximately 50 ml or 100 ml of distilled/deionised water (H₂O) into a 250 ml beaker or conical flask (use a conical flask if not using a magnetic stirrer), and add a few drops of phenolphthalein indicator.

2. - Adjust (titrate) the distilled H₂O until a pink colour end point is achieved that persists.

Note:you do not need to record the amount (titre) of 0.1 M NaOH used.