The reversible interconversion between the yellow chromate () and orange dichromate () ions is heavi — d and f Block Elements Chemistry Question

💡 Solution & Explanation

The equilibrium is: $2CrO_4^{2-} + 2H^+ \rightleftharpoons Cr_2O_7^{2-} + H_2O$. Adding acid ($H^+$) pushes the reaction right, forming orange dichromate. Adding alkali ($OH^-$) neutralizes the $H^+$, pulling the reaction left, forming yellow chromate. Critically, this is strictly not a redox reaction; Chromium remains entirely in the $+6$ oxidation state in both structural forms.