Answer the following questions: Complete and balance the following chemical equation: Why do…
Answer the following questions:
(i)
Complete and balance the following chemical equation:
$\text{KMnO}_4 + \text{H}_2\text{SO}_4 + \text{H}_2\text{S} \rightarrow \text{_____} + \text{_____} + \text{_____} + \text{_____}$
(ii)
Why do transition metals form alloys?
(iii)
Potassium dichromate ($\text{K}_2\text{Cr}_2\text{O}_7$) acts as a powerful oxidising agent in acidic medium. Explain.
Answer
Answer (i)
AIWritten by AI (gemini) - it can contain mistakes.
Balanced equation:
$2\text{KMnO}_4 + 3\text{H}_2\text{SO}_4 + 5\text{H}_2\text{S} \rightarrow \text{K}_2\text{SO}_4 + 2\text{MnSO}_4 + 8\text{H}_2\text{O} + 5\text{S}$
Answer (ii)
AIWritten by AI (gemini) - it can contain mistakes.
Transition metals have similar atomic radii and crystal structures. In the molten state, atoms of one transition metal can easily substitute for atoms of another in the crystal lattice, readily forming alloys.
Answer (iii)
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In acidic medium, potassium dichromate acts as a strong oxidizing agent because $\text{Cr}_2\text{O}_7^{2-}$ gets reduced to $\text{Cr}^{3+}$, accepting 6 electrons per dichromate ion:
$\text{Cr}_2\text{O}_7^{2-} + 14\text{H}^+ + 6e^- \rightarrow 2\text{Cr}^{3+} + 7\text{H}_2\text{O}$ ($E^\circ = +1\cdot33\text{ V}$).
From ISC 2027 Specimen Chemistry Paper 1, question 15.