Answer:
2NO + 4H+ + 3SO2−4 ⟶ 2NO−3 + 3SO2 + 2H2O
Step-by-step explanation:
Step 1: Write the half reactions:
NO ⟶ NO−3
SO2−4 ⟶ SO2
Step 2: Balance all elements except oxygen and hydrogen (no change):
NO ⟶ NO−3
SO2−4 ⟶ SO2
Step 3: Balance oxygen atoms by adding water molecules:
NO + 2H2O ⟶ NO−3
SO2−4 ⟶ SO2 + 2H2O
Step 4: Balance hydrogen atoms by adding hydrogen ions:
NO + 2H2O ⟶ NO−3 + 4H+
4H+ + SO2−4 ⟶ SO2 + 2H2O
Step 5: Add electrons to balance the charge:
NO + 2H2O ⟶ NO−3 + 4H+ +3e−
4H+ + SO2−4 + 2e− ⟶ SO2 + 2H2O
Step 6: Multiply the two half-reactions so the number of electrons in one reaction equals the number of electrons in the other reaction:
2NO + 4H2O ⟶ 2NO−3 +8H+ + 6e−
12H+ + 3SO2−4 + 6e− ⟶ 3SO2 + 6H2O
Step 7: Add the balanced half-reactions and cancel species that appear on both sides of the equation:
2NO + 4H+ + 3SO2−4 ⟶ 2NO−3 + 3SO2 + 2H2O