Why do some acids and bases affect K2Cr2O4 and others do not?


I am referring to CH3COOH, K2SO4, KOH, C2H5OH, Ca(OH)2 and NH3. As well, why does NH3 act like a base?

potassium chromate (VI) is yellow and will remain yellow except in the presence of H^+ ions... as far as I know.

You have examples of what bases do that? Or which do not?