Chromium and Dichromate Ions Uses

Uses of Dichromate

• Employed in volumetric analysis for redox titrations, specifically to determine ferrous ions and iodides.
• Integral in the leather industry for chrome tanning processes.
• Utilized in the production of multiple chromium compounds, including potassium chromate and chromium trioxide.
• Contributes to processes in calico printing, dyeing, and photography, especially in hardening gelatin film.
• Functions effectively as an oxidising agent in various chemical reactions.
• Potassium dichromate combined with sulfuric acid serves as an effective cleaning agent for laboratory glassware.

Reaction with Hydrogen Peroxide

• In an acidified solution, potassium dichromate reacts with hydrogen peroxide to yield blue perchromate ($CrO_5$).
• The reaction is represented as: $Cr_2O_7^{2-} + 2H^+ + 4H_2O_2 \longrightarrow 2CrO_5 + 5H_2O$.

Structure of Dichromate and Chromate Ions

• Chromate ion features a tetrahedral geometry, characterized by two tetrahedras sharing a Cr-O-Cr bond at an angle of 126°.
• Dichromate ion is composed of two chromate ions linked through a shared oxygen atom.
• Chromium in both the chromate and dichromate ions exhibits an oxidation state of +6.