Perchloric acid Solution Preparation
- Take about 500 ml of anhydrous glacial acetic acid & about 25 ml Acetic anhydride in a cleaned and dried 1000 ml volumetric flask.
- Add about 8.5 ml of Perchloric acid (About 70%) with continues stirring.
- Cool the solution.
- Make up the volume 1000-ml with anhydrous glacial acid. Mix solution thoroughly.
- Keep the solution for at least (24 hours) for the excess acetic anhydride to be combined. Then carry out the determination of water. If the water content exceeds 0.05% add more acetic anhydride. If the solution contains water, add sufficient water to obtain a content of water between 0.02 % to 0.05%.
- Allow the solution to stand for 1 day and again titrate the water content. The solution so obtained should contain between 0.02% and 0.05% of water. Standardize the solution.
Perchloric acid Solution Standardization
- Accurately weigh about 700 mg of Potassium phthalate, previously crushed lightly and dried at 120° for 2 hours, and dissolve it in 50 ml of glacial acetic acid in a 250-ml)conical flask.
- Add 2 drops of Crystal Violet, and titrate with the perchloric acid solution until the violet color changes to blue-green.
- Deduct the volume of the perchloric acid consumed by 50 ml of the glacial acetic acid.
- Each 20.42 mg of Potassium phthalate is equivalent to 1 ml of 0.1N perchloric acid.
- Calculate the molarity by the following formula:
KHC8H4O4 in gm
N= ---------------------------
0.20423 x HClO4 in ml
N= ---------------------------
0.20423 x HClO4 in ml
hello mr ankur , i just wanna ask about the end point of hclo4 standardization, is it blue-green or yellowish green (emerald green) because in other references said that, and i always trying to make it in blue-green but i never got the value exactly, because the range of blue-green to yellowish green is far enough. would you please thanks :D
ReplyDeleteThat is very slight change from violet to blue green, look it carefully.
DeleteHi would you like to guide me either 0.1 m and 0.1 N of perchloric are same plz tell how to prepare
ReplyDeleteHello, Can you please explain the reason for second end point peak in potentiometric titration of perchloric acid with acetic acid and KHP
ReplyDelete