Answer to Question #236578 in General Chemistry for Mickayla

Question

Complete and balance the following redox equation. What is the coefficient of H₂S when the equation is balanced with the set of smallest whole numbers?

H₂S + MnO₄^- → Mn²⁺ + SO₄^2– (acidic solution)

1. 1
2. 2
3. 4
4. 5
5. None of the above.

Answer 1

MnO₄^-$\to$Mn²⁺

^H₂ S$\to$SO₄^2-

MnO₄^- $\to$ Mn²⁺ +4H₂O

H₂S +4H₂O$\to$ SO₄^2-

MnO_{4 +}8H⁺ $\to$ Mn²⁺ +4H₂O

H₂S +4H₂O$\to$ SO₄^2- +10H⁺

MnO₄^- +8H⁺ +5e$\to$ Mn²⁺ +4H₂O ...(1)

H₂S +4H₂O$\to$ SO₄^2- +10H⁺ +8e^- ...(2)

8MnO₄ +64H⁺ 4Oe^- $\to$ 8Mn²⁺ +32H₂O ...(3)

5H₂S + 20H₂O $\to$ 5SO₄^2- + 40e^- ...(4)

8MnO₄ + 64H⁺ 4Oe^- +5H₂S +20H₂O$\to$ 5SO₄^2- +8Mn²⁺ +32H₂O +5SO₄^2- +5OH⁺ +40e^-

8MnO₄^- (aq) +14H⁺ (aq) +5H₂S (aq) $\to$ 5SO₄^2- (aq) +8Mn^{2+ (aq)} +12H₂O (l) +5SO₄^2- (aq)

The coefficient of H₂S is 5