Question about chromate-dichromate equilibrium?

[HelloMotto]

Ok so when i add HCl to a chromate solution, it turns orange (dichromate) because the equilibrium shifts to the right, inorder to reduce the excess hydrogen ions from the HCl Acid.

But when I add HCl to dichromate, the color changes the same. How do i explain this phenomenon.

and is this the right equation?


2[CrO4]-2 + [H]+ <---> [Cr2O7]-2 + H2O

 

[Borek]

Equation is OK.

Take a look at it - what would you expect if you dissolve dichromate in pure water?

 

[Blueshift5]

The phenomenon you are observing is due to the fact that both chromate (CrO4)-2 and dichromate (Cr2O7)-2 ions exist in equilibrium with each other in solution. When HCl is added to a chromate solution, the equilibrium shifts to the right, as you mentioned, resulting in the formation of more dichromate ions. However, when HCl is added to a dichromate solution, the equilibrium shifts to the left, resulting in the formation of more chromate ions. This is why the color change is the same in both cases.

The equation you have provided is correct and represents the equilibrium between chromate and dichromate ions in solution. It is important to note that the equilibrium constant for this reaction is highly dependent on the concentration of hydrogen ions and can be affected by factors such as temperature and pressure. Therefore, the exact color change observed may vary slightly in different experimental conditions.

Overall, the chromate-dichromate equilibrium is a complex and dynamic system that can be influenced by various factors. it is important to carefully consider all variables and experimental conditions when studying this equilibrium.