Answer to Question #122361 in General Chemistry for Johannes Steven

Question

29. For the following reaction, which element undergoes a change in oxidation number of +1? P4 + 3OH + 3H2O = PH3 + 3H2PO2? 30. When the equation for the overall reaction is balanced for: MnO4^- + HSO3^- = MnO4^-2 + SO4^-2, using the smallest integer coefficients possible, what is the coefficient of MnO4^-2? 31. The oxidation number of chromium in the dichromate, Cr2O7^-2 is: 32. MnO4^- + HSO3^- = MnO4^-2 + SO4^-2. For the above reaction, the oxidizing agent is _ and the reducing agent is _.

Answer 1

Ans.

1. Phosphorus (P) undergoes (+1) change in oxidation number from P to H₂PO₂^-1
2. The coefficient of MnO4^-2 is 2. The balanced equation is 2MnO4^- + HSO₃^- + H₂O= 2MnO4^-2 + 3H⁺ + SO₄^-2
3. Oxidation number of chromium in the dichromate is +6
4. MnO₄^- is the oxidizing agent and HSO₃^- is the reducing agent.