Question

Problem 1: Balance the following reaction in (a) acidic solution and (b) basic solution MnO2 (s) + H Asos (aq) → Mn2+ (aq) + HASO (aq) (a) Acidic solution 1. Split the reaction into two half-reactions. Mn q + ac Mnat HAs Oy > Hj As Oy + ae" 2. Consider the following half reaction: MnO2 (s) → Mn2+ (aq) Balance everything but oxygen and hydrogen atoms. MnOade > Moi 3. Take your answer to (2) and balance the oxygen by adding a water to add oxygen where needed. Mn Oathe Mn" + H₂O 4. Take your answer to (3) and balance the hydrogen by adding in H+ where needed (do not forget the charge on the H!). Mon Oat det Ht Mat + H2O 5. Take your answer to (4) and balance the charges by adding electrons to the more positive side of the reaction until the charges are equal.

Answer 1

given reaction is - Min 02(k) + H₂ R03 (aq) multiaa) + H ₂ Asocans @ Acidic Medium/ solution 1. two half reactions are MnO2 – Mu2+ and thAs Oz - H₂ AsO4 Consider half reaction Madr – M.2+ 3 Balancing oxygen by adding Hao Madz Mu2+ + 240 4 Balancing hydrogen by adding Ht (acidic) Mulz & 4H+ Mn 2 + + 2H2O 5 Balancing charge by adding é MnO2 + 4H+ + 20 - My 2+ + 2H₂O 6 consider half reaction H3 AsOz - H3 As Oy In the same way H3 AsO 3 + H2O → H3 AsO 4 ( for oxygen) HB AsO 3 + H2O H3 AsO 4 + 2H+ (for Hydrogen) Hz ASO3 + H2O H3 AsO 4 + 2H+ + 20 (Charge) combining 9 & ① and ② MnO2 + H₂ As Oz + 4H+ + 20 - Mult + 2H2O + M3 AsOy + 2H+ + 20 After cleaning up @ geves MnO₂ + H₂ AsO ₃ + 2H+ - Mu2+ + H₂O + Mauds Oy (Balanced for mass and charge.)

6 Basic Medium/ Solution @ Half reactions MnO2 & Mu2+ MASO3 H₂ AO Consider half reaction MnO₂ - Muz+ 2 Balancing oxygen MnO2 Mu2+ + 2H2O 4 Balancing nydrogen Muda +244 +40H & Mu2+ + 2H₂O + you. 5 consider half reaction - H₃ AsOy (and do the same as above) H3 ASO3 + H₂O - Hanson (for oxygen) H₂ ASO3 + H2O + 204 H3 AsO4 + 2H* + 204 Combining 6 and ① gives MnO₂ + H ₂ As Oz & 5H₂O + 204 - Mu2+ + H₂ As 04 + 4H₂O - a 404 1. Muo2 + H₂ AS O3 + H₂O Mn2t + H₂ AsO4 + 204 (on for basic medium) H3 AsO₂ or