Question

how will prepare 100ml of 0.2 N K2Cr2O7 solution​

Answer 1

To make up the the acidified dichromate(VI) solution: dissolve 2 g of potassium dichromate(VI) in 80 cm3 of deionised or distilled water and slowly add 10 cm3 of concentrated sulfuric acid to the solution, with cooling. Label the solution TOXIC and CORROSIVE.  Dissolve potassium dichromate in water. Pour solution into crock, slowly add sulfuric acid. Keeps until solution turns dark brown, depends upon use. Label, date, initial.  

Potassium Dichromate Solution Preparation

Weigh 4.9 g of potassium dichromate, previously powdered and dried in a desiccator for 4 hours.

Dissolve in sufficient water to produce 1000 ml. Standardize the solution in the following manner.