Question

To a solution of 5 drops of 0.3 M K2CrO4 and 2 drops of 0.3 M NaOH add, a drop at a time 0.1 M Ba(NO3)2 until a change is noted

what would be the visual predictions and colour changes or changes in the number of states?

Answer 1

If barium chromate is formed, it is a precipate, lemon yellow
If barium dichromate is formed, is is soluble, and the solution is orange.

Potassium chromate solution is yellow (slight red tinge)

Now what is neat, is to add a few drops of acid to change the pH.