Page 2: Chromium Compounds and Their Reactions
This page delves deeper into the behavior of chromium compounds in different environments and their redox properties.
Stability of chromates and dichromates:
- K₂CrO₄ is stable in basic conditions but converts to K₂Cr₂O₇ in acidic environments.
- K₂Cr₂O₇ is stable in acidic conditions but transforms to K₂CrO₄ in basic environments.
Definition: Chromates are yellow, while dichromates are orange, providing a visual indicator of the solution's pH.
Oxidizing properties of K₂Cr₂O₇:
- In acidic conditions, Cr₂O₇²⁻ is reduced to Cr³⁺, changing color from orange to green.
Reducing properties of Cr³⁺ salts:
- Cr³⁺ can be oxidized to CrO₄²⁻ in basic conditions with strong oxidizing agents like H₂O₂.
Example: The thermal decomposition of ammonium dichromate produces Cr₂O₃, nitrogen, and water, demonstrating the redox behavior of chromium compounds.
Redox reactions involving chromium compounds:
- Various substances can act as reducing agents e.g.,NO2−,H2O2,SO32− or oxidizing agents e.g.,MnO4−,ClO−,O3 in reactions with chromium compounds.
Highlight: Understanding these redox reactions is essential for solving pierwiastki bloku d zadania maturalne.