Chromate (VI)-dichromate (VI) equilibrium, 3 of 3. Chromate (VI) ((CrO4)2-) and dichromate (VI) ((Cr2O7)2-) ions exist in an aqueous solution in equilibrium, according to the equation: (CrO4)2- + (H)+ <--> (Cr2O7)2- + H2O. According to Le Chatelier's Principle this equilibrium can be shifted by changing concentration of (H)+ ions (i.e. the pH of the solution). This is demonstrated in this series of photos. Photo 1 shows 4 mL of 0.25M solution of potassium chromate (VI) (K2CrO4, yellow). Photo 2 was taken after 0.5 mL of 1M sulfuric acid (H2SO4) was added and the colour changed to orange, indicating dichromate (VI) ions. Photo 3 was taken after 1.5 mL of 1M potassium hydroxide (KOH) was added and the colour changed back to yellow indicating chromate (VI) ions. | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Giphotostock |
Bildgröße: | 3391 px × 5113 px |
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Eigentums-Rechte: | nicht erforderlich |
Restrictions: | - |