Question

Applying Le Chateliers principle, what can you conclude about the change `2CrO_4^(-2) -> Cr_2O_7^(-2)` and its dependence on hydrogen ions, `H^+`?

Answer 1

Adding more hydrogen ions would favour the formation of `Cr_2O_7^(-2)`

Removing hydrogen ions would favour the formation of `CrO_4^(-2)`

Explanation:

The net ionic equation is:

`2CrO_4^(-2) + "2H"^"+"⇌ Cr_2O_7^(-2) + "H"_2"O"`

There are `2 H^+` ions on the LHS and none on the RHS.

Based on Le Chateliers Principle;

Adding more hydrogen ions (making conditions more acidic) would favour the formation of `Cr_2O_7^(-2)` because the equilibrium would shift to the side with fewer hydrogen ions to balance the system.

Removing hydrogen ions (making conditions more basic) would favour the formation of `CrO_4^(-2)` because the equilibrium would shift to the side with more hydrogen ions to balance the system.