[angst]

Now, I have to standardize K2Cr2O7 against As2O3, can somebody show the calculation to get the concentration of K2Cr2O7??

Procedure as below:   

a)   Weigh accurately 0.2g of dry primary standard, add 10ml of 5M Sodium Hydroxide solution, and stir until the solid is completely dissolved.
b)   Then, add 100ml of distilled water, 10ml of concentrated Hydrochloric Acid, and one drop of 0.025M Potassium Iodide.
c)   Titrate with Potassium Dichromate, drop wise near the end, to the first pink color permanent for 30 seconds.
d)    Run a blank, using the same amounts of alkali, water, acid, and catalyst as in the titration.

Thanks.

[Borek]

Please read forum rules.

Hint: AsO₄^3-