Question

Cr2O72- + OH- → CrO42- + H2O​

Answer 1

Answer:

[9Cr2O7 2-] [ H2O] / [H+]^2 [CrO4 2-]^2

part 2 > The equilibrium between chromate ion (CrO42-) and dichromate ion (Cr2O72-) was studied. The indication for which way the reaction shifts when changes were made in the system is based on the color of these two ions in solution: chromate ion is bright yellow in solution, whereas dichromate ion is bright orange. So, if the solution turned orange when you added something to it, the equilibrium was shifted to the right; if the solution turned yellow, the equilibrium was shifted to the left.

So addinh acid i.e. H+ ions will shift the eq. to the right and change the colour to orange

3> adding base will change the colour to yellow as oh- ions wil shift the reaction to left

4> The colour will change to orange as on the left there will be more h30+ ions and the reaction would move right