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Answer the following.
Potassium dichromate (K₂Cr₂O₇) acts as a powerful oxidising agent in acidic medium. Explain.
Potassium dichromate ($\text{K}_2\text{Cr}_2\text{O}_7$) acts as a powerful oxidising agent in acidic medium. Explain.
Answer
Answer
Official answer keyIn the presence of dilute sulphuric acid, $\mathrm{K_2Cr_2O_7}$ liberates nascent oxygen, so it acts as a powerful oxidising agent: $\mathrm{K_2Cr_2O_7 + 4H_2SO_4 \rightarrow K_2SO_4 + Cr_2(SO_4)_3 + 4H_2O + 3[O]}$. The $\mathrm{Cr^{6+}}$ in dichromate is reduced to the stable $\mathrm{Cr^{3+}}$.