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Narrative
These four Petri dishes contain acidic dichromate solution. Ethanol, a primary alcohol, is added to the first dish. 2-Propanol, a secondary alcohol, is added to the second dish. 2-Methyl-2-propanol, a tertiary alcohol, is added to the third dish. The fourth is left as a control. After 20 seconds, the ethanol solution becomes green then blue. The 2-propanol produces the same sequence of color changes but at a slower rate. Primary and secondary alcohols are oxidized by dichromate; whereas tertiary alcohols do not react. The yellow chromium(VI) ion is reduced to blue chromium(III).

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