chemistry

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. 👁
  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. 👎

Respond to this Question

First Name

Your Response

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

  2. Chemistry

    Classify the following reactions as precipitation reactions, oxidation-reduction reactions, or acid-base reactions. 1)2NaCl(aq)+K2H2Sb2O7(aq)==Na2H2SbO7(s)+2KCl(aq) 2)(CH3COO)2Cu(aq)+(NH4)2C2O4(aq)==CuC2O4(s)+2CH3COONH4(aq)

  3. chemistry

    2. What is the reduction half-reaction for the following unbalanced redox equation? Cr2O72– + NH4+ Cr2O3 + N2 A.) Cr2O3 -> Cr2O7^2– *B.) Cr2O72– -> Cr2O3 C.) NH4+ -> N2 D.) N2 -> NH4+ 3. Which oxidation-reduction reactions

  4. Chemistry - Please check

    d) 2Al(s) + Fe2O3(s)  2Fe(l) + Al2O3(s) Oxidation 2Al(s)  2Al+ + 2e- Reduction Fe23+ + 3e-  2Fe(l) Oxidation numbers for chlorine HCl = -1 MnO2(s)= +4 KMnO4(s)= +7 Oxidation numbers for manganese Mn(s)= ? MnCl2(s)= +7

  1. 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

  2. chemistry

    Fe2+(aq) + Cr2O7 2- (aq) →Fe3+(aq) + Cr3+(aq) Balance the equation by using oxidation and reduction half reactions. What is smallest possible integer coefficient of Cr3+ in the combined balanced equation?

  3. Chemistry

    Identify the oxidation-reduction reactions among the following: 1. Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s) 2. 2Na(s) + Cl2(aq) → 2NaCl(s) 3. 2Mg(s) + O2(g) → 2MgO 1 and 2 only 2 and 3 only 1 and 3 only All of 1, 2, and 3 None of

  4. Chemistry

    Dr.Bobb222 please help balance the following oxidation-reduction reactions, which occur in acidic solution, using the half-reaction method. (Use the lowest possible coefficients. Include states-of-matter under the given conditions

  1. Chemistry

    Identify the oxidation-reduction reactions among the following: 1. Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s) 2. 2Na(s) + Cl2(aq) → 2NaCl(s) 3. 2Mg(s) + O2(g) → 2MgO Identify the oxidation-reduction reactions among the following: 1

  2. chemistry

    "Write equations for the half-reactions that occur at the anode and cathode for the electrolysis of the following aqueous solution: CuBr2(aq)" Possible oxidation reactions: 1. 2Br- -> Br2 + 2e- = -1.09 2. 2H2O -> O2 + 4H+ + 4e- =

  3. Chem

    what occurs during the reaction below 4Hcl+MnO2-->MnCl2+2H2O+Cl2 1.the manganese is reduced and its oxidation number changes from +4 to +2. 2.the manganese is oxidized and its oxidation number changes from +4 to +2. 3.the

  4. 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

You can view more similar questions or ask a new question.