How to prepare sodium hydroxide solution

How to prepare sodium hydroxide solution

  SODIUM HYDROXIDE SOLUTION 0.1 N  


          Preparation        

Take 1g of sodium hydroxide (NaOH) in 250-mL volumetric flask. Make up dioxide-free water. Mix well, and storein a tight polyolefin container.


                      Standardization             

Crush 1 to 2 g of primary standard potassiumh hydrogen phthalate (KHC8H4O4) and dry in a glass container at 120°C for 2 h. Stopper the containern andcool in  a desiccator.

weight accurately 0.95 g of the dried KHC8H4O4, and transfer to a 250-mL conicalflask. Add 100-mL of carbon dioxide-free water, stir gently to dissolve the sample, add 3 drops of a 1.0 % solution of phenolphthalein in alcohol, and titrate with NaOH solutions end point color pink.


                         Calculation                 

Normality of the NaOH solution(N), as
follows:
 N = A /0.20423 *B

Where
A - gram of KHC8H4O4 used,
B - used ml of Naoh solution in titrition.

Ex-
0.9503 gm of KHC8H4O4
46.7 ml used of Naoh solution.

Normality of the NaOH = 0.9503/0.20423*46.7= 0.0996 N




                         Stability                  

The use of polyolefin containers eliminates some of the
difficulties attendant upon the use of glass containers, and their
use is recommended. Should glass containers be used, the
solution must be standardized frequently if there is evidence of
action on the glass container, or if insoluble matter appears in
the solution.

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