Question

What happen when a solution of potassium chromate is treated with an excess of dil. Nitic acid?
A. `Cr_(2)O_(7)^(2-)` and `OH^(-)` are formed
B. `CrO_(4)^(2-)` is reduced to +3 state of Cr
C. `CrO_(4)^(2-)` is oxidized to +7 state of Cr.
D. `Cr^(3+)` and `Cr_(2)O_(7)^(2-)` are formed.

Answer 1

Correct Answer - A
`Cr_(2)O_(7)^(2-) + OH^(-) hArr2CrO_(4)^(2-) + H^(+)`
In the acidic medium, the equilibrium gets shifted to left .
Therefore, `Cr_(2)O_(7_^(2-)` and `OH^(-) ions are formed.