Standardization of 1 Molar Hydrochloric acid solution
Standardization of 1 Molar Hydrochloric acid solution
¨ Accurately
weigh about 5.0 gram (5000mg)of tromethamine.
¨ Dried
as per instructions given on label claim, however if no such instructions are available
then dried for 3 hours at 105◦C in oven.
¨ Dissolve
in 50ml of carbon-dioxide free water.
¨ Add
2 drops of bromocresol indicator.
¨ Titrate
with 1 molar Hydrochloric acid with constant stirring until a pale yellow color
is produced.
¨ Each
ml of 1 molar Hydrochloric acid is equivalent to 121.14 mg of tromethamine.
¨ Calculate
the molarity using following formula
¨ Molarity=
weight of tromethamine taken
molecular weight of tromethamine x ml
of 1 M HCl used
¨ Molarity=
weight of tromethamine taken
121.14 x ml of 1 M HCl used
OR
¨ Accurately
weight 1 gram (1000mg)of anhydrous Sodium carbonate and dried is as per the
instructions given on the label.
¨ However
if no such instructions are available then dried the Sodium carbonate for 1
hour at 270◦C.
¨ Dissolve
it in 100 ml of carbon-dioxide free water.
¨ Add
0.1 ml of methyl orange solution.
¨ Titrate
with 1 molar HCl solution with constant stirring until the solution becomes
reddish yellow.
¨ Boil
it for 2 minutes and continue the titration with constant stirring until the
reddish yellow color restored.
¨ Each
ml of 1 molar hydrochloric acid is equivalent to 52.99 mg of Sodium carbonate
anhydrous.
¨
¨ Molarity = weight of anhydrous sodium
carbonate taken
molecular weight of sodium carbonate anhydrous
x ml of 1 M HCl used
¨ Molarity=
weight of anhydrous sodium carbonate taken
52.99 x ml of 1 M HCl used
Note
¨ Standardization
is only required when the solution is used for quantitative analysis.
¨ In
case of qualitative analysis such as pH adjustment, dissolution medium or
diluent there is no need of standardization.
0 Comments