0.1 N Sodium Hydroxide ( Naoh)
Preparation of 0.1 N Sodium Hydroxide
- Take 1g of Sodium hydroxide (NaOH) in 250-ml volumetric flask.
- Make up dioxide-free water.
- Mix well, and store in a tight polyolefin container.
Standardization of 0.1 N Sodium Hydroxide
- Crush 1 to 2 g of primary standard potassium 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 conical flask.
- 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.
Normality of the NaOH solution(N), as
N = A /0.20423 *B
A – gram of KHC8H4O4 used,
B – used ml of Naoh solution in titration.
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
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.