Ask questions and get helpful answers.

Balance following oxidation reduction reactions using oxidation states method?

a) Cl2(g) + Al(s) --> Al3+(aq) + Cl-

b.) O2(g) + H2O(l) + Pb(s) --> Pb(OH)2(s)

c) H+(aq) + MnO4-(aq) + Fe2+(aq) --> Mn2+(aq) + Fe3+(aq) + H2O(l)

  1. 👍
  2. 👎
  3. 👁
  4. ℹ️
  5. 🚩
1 answer
  1. Cl2(g) + Al(s) --> Al3+(aq) + Cl-

    Cl2 + 2e --> 2Cl^-
    Al ===> Al^3+ + 3e

    Multiply equation 1 by 3 and equation 21 by 2 and add. Cancel the electrons.

    Here is MnO4^- from part c done this way in detail
    MnO4^- ==> Mn^2+

    1. The oxidation state Mn on the left is +7; on the right is +2. Add electrons to the appropriate side to balance the change in electrons.

    2. MnO4^- + 5e ==> Mn^2+

    3. Count the charge on the left and right, then add H^+ (since this is an acid solution but add OH^- if a basic solution) to the appropriate side to balance the charge..
    charge on left is -6; on the right is +2 so I add 8H^+ to left.

    4. MnO4^- + 5e + 8H^+ ==> Mn^2+

    5. Then add H2O (makes no difference in the previous step if you added H^+ or OH^-) to the appropriate side to balance.
    MnO4^- + 5e + 8H^+ ==> Mn^2+ + 4H2O

    6. Check it.
    a. Mn goes from 7 to 2; add 5e to 7 to make 2.
    b. count charge on left and right to see if it balances. 2+ on left; 2+ on right
    d. Check that atoms balance.
    1Mn on left and right; 8H on left and right; 4 O on left and right.
    Success.

    Here is an example of one (same MnO4^-) using OH but I won't go through the explanation. You can read that step by step from above.

    MnO4^- --> MnO2
    Mn is 7 on left and 4 on right. Add 3e
    MnO4^- + 3e ==> MnO2

    Charge on left is -4; on right is 0. Add 4OH^- to right.

    MnO4^- + 3e ==> MnO2 + 4OH^-

    Then add H2O to the left.]
    MnO4^- + 3e + 2H2O ==> MnO2 + 4OH^-

    I'll let you check it but I know it's right because I checked it too. ALWAYS check it; that way you will know if you have it right or wrong. If wrong you can redo it and get it right. There is NEVER and excuse for THINKING you have it right and getting it wrong or THINKING it wrong and getting it right. You CAN know it's wrong but not know how to fix it to right. ;-)

    1. 👍
    2. 👎
    3. ℹ️
    4. 🚩

Answer this Question

Similar Questions

  1. chemistry

    MnO4–(aq) + Cl–(aq) Mn2+ + Cl2(g) (unbalanced) i. Write the reduction and oxidation half-reactions (without electrons). (.5 point) ii. Balance the equations for atoms (except O and H). (.5 point) iii. Balance the equations for atoms O and H using H2O

  2. chemistry- electrochemical cell

    What makes this an oxidation-reaction? 3Ag2S+2Al(s) -> Al2S3+6 Ag(s)? Write the half-reactions showing the oxidation and reduction reactions. Identify which is the oxidation reaction and which is the reduction reason. What is oxidized in the reaction? What

  3. chemistry

    Which statement best describes the oxidation numbers of the atoms found in magnesium chloride? A. Magnesium has a 22 oxidation number and chlorine has 1+ oxidation number. B. Magnesium has 1+ oxidation number and chlorine has a 12 oxidation number. C.

  4. chemistry-balanced redox equations

    Use the following steps to balance the redox reaction below: Mg + Au+ Mg2+ + Au a. Write the oxidation and reduction half-reactions. Make sure each half-reaction is balanced for number of atoms and charge b. Multiply each half-reaction by the correct

  5. chemistry

    Mg + Au+ -> Mg2+ + Au what is the oxidation and reduction half reactions

  6. Chem Check Please!!!

    1) Assuming the following reaction proceeds in the forward direction, 3 Sn4+(aq) + 2 Cr(s) ---> 3 Sn2+(aq) + 2 Cr3+(aq) a.Sn4+(aq) is the reducing agent and Cr(s) is the oxidizing agent. b.Cr(s) is the reducing agent and Sn2+(aq) is the oxidizing agent.

  7. Chemistry

    I have this question: Consider the dichloropropane molecule, C3H6Cl2. Despite being a molecular compound, oxidation states can be assigned to the elements in butane. +1Calculate the oxidation state of the carbon atoms. The oxidation state of the Cl atoms

  8. chem

    Q: Calculate ℰ° values for the following cells. Which reactions are spontaneous as written (under standard conditions)? Balance the equations. Standard reduction potentials are found in the Standard Reduction Potentials table. (Use the lowest possible

  9. Chemistry - Redox

    Balance the following redox reactions by inserting the appropriate coefficients. Al + MnO2 --> Al2O3 + Mn HNO3 + H2S --> NO + S + H20 Initially, I know the first step is to find assign all the oxidation numbers for the products and reactants listed, but am

  10. chem

    Balance the following oxidation-reduction reaction in acid solution: SO32- + MnO4- --> SO42- + Mn2+ + H2O

Still need help?

You can ask a new question or browse existing questions.