Homework Answers

Write the oxidation half-reaction and reduction half-reaction, and shorthand electrochemical notation for the following.

1. Mg+H^+ -> Mg^ 2+ +H 2

2. KI + Cl2 -> KCl + I2

3. Cr^ + +Sn^ 4+ Cr^ 3+ +Sn^ 2+

4. 3 Hg^ 2+ +2 Fe (s) 3 Hg 2 +2 Fe^ 3+

5. 2 As (n) + 3 Cl₂ (g) → 2 AsCla

6. NaBr + Cl₂ ⇒ NaCl + Br₂

7. F*e_{2}*O_{3} + CO -> Fe + C*O_{2}

8. CO + I_{2}*O_{5} -> C*O_{2} + I_{2}

2 Fe^ 3+ (aq) +Sn^ 2+ 2 Fe^ 2+ +Sn^ 4+ (aq)

10. Chlorine gas oxidises Fe2+ ions to Fe³+ ions. In the process, chlorine is reduced to chloride ions.

Calculate the entropy change, So for the following process.

a. Melting of ice at 0°C (heat of fusion of ice is 6.02 kJ/mol)

The following practice problems are prepared for you to polish and enrich your understanding in determining the oxidizing state of elements and further widen your understanding about the differences between an oxidizing agent and a reducing agent.

Assign oxidation state to the underlined element.

1) Cl₂

2) SO₂

3) K₂0₂

4) Cr₂07-²

5) Na₂O₂

6) Na₂S₂O3

7) NaN3

8) CH4

9) Fe₂O3

10) MnO₂