When technical sodium dichromate is used, the solution should be filtered with suction, before it is added to the hydroquinone, in order to remove any insoluble impurities.
"Organic-Syntheses"
Conant, James Bryant
It is essential that the stirring should be most efficient, so that when the mixture becomes thick the dichromate will be evenly distributed throughout the liquid, as rapidly as it is added.
"Organic-Syntheses"
Conant, James Bryant
The amount of solid sodium dichromate given is for the dry crystalline compound containing two molecules of water of crystallization.
"Organic-Syntheses"
Conant, James Bryant