Which reagent gives the same visible change for propanol and Propanal:
Correct answer: B. K2Cr2O7/H+
- A. 2, 4 - DNPH
- B. K2Cr2O7/H+
- C. Conc H2SO4
- D. Ag mirror test
Explanation
Orange color discharged. when it comes to propanol and propanal, both of them can show a similar visible change when treated with the reagent K2Cr2O7/H+. Let me explain what happens.When propanol or propanal is treated with K2Cr2O7/H+, it undergoes an oxidation reaction. The orange-colored K2Cr2O7, also known as potassium dichromate, acts as an oxidizing agent in the presence of an acid (H+).In the case of propanol, it gets oxidized to propanal. The orange color of K2Cr2O7 changes to green as it gets reduced to Cr3+ ions. This change in color is a visible indication of the oxidation reaction taking place.Similarly, when propanal is treated with K2Cr2O7/H+, it also undergoes oxidation. However, since propanal is already an aldehyde, it cannot be further oxidized. So, in this case, the orange color of K2Cr2O7 will still change to green, indicating the reduction of the reagent.In both cases, the change in color from orange to green is a visible sign that an oxidation reaction has occurred.
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About Aldehydes and Ketones
Aldehydes and ketones contain the polar carbonyl group, but aldehydes are generally more readily oxidised and more reactive than ketones. Coverage includes preparation by oxidation or reduction routes, nucleophilic addition of reagents such as hydrogen cyanide and bisulfite, and tests that distinguish aldehydes from ketones.
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