chemistry

posted by .

How do I balance a redox reaction for NaI + H2SO4 = H2S + I2 + Na2SO4 + H2O? I don't understand how to balance the electron loss for Iodine.

  • chemistry -

    First we note that we have 1 I on the left and 2 on the right. In order to compare apples with apples we need to have the same number; therefore, we stick a 2 on the left so we start with the same number of I atoms.
    2I^- ==>I2
    So we have changed from -2 (for two I atoms) to zero (for two I atoms). That is a loss of two electrons.
    2I^- ==> I2 + 2e
    That first step is almost never addressed in redox instructions and it is the difference between success and failure. It is common to do this with I^- ==> I2, Cr2O7^2- ==> Cr^3+, Cl2 ==> Cl^-, S2O4^2- ==> S4O6^2-, C2O4^2- ==> CO2, etc.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. chemistry

    how do u do a redox balance of the following reaction : Fe(NH4)2(SO4)2*6H2O + H2C2O4 + K2C2O4 + H2O2 -> K3Fe(C2O4)3*3 H2O + (NH4)2SO4 + H2SO4 +H2O i only know Fe2+ -> Fe3+ +1e-
  2. Chemistry

    NaHCO3 + H2SO4 Na2SO4 + H2O + CO2 Use minimal integer numbers to balance the reaction. Include physical states in your answer.
  3. Chem30

    Balance the following redox reations: K2Cr2O7 + Nal + H2SO4 --- Cr2(SO4)3 + I2 + H2O + Na2SO4 + K2SO4
  4. Chem30

    Balance the following redox reations: K2Cr2O7 + Nal + H2SO4 --- Cr2(SO4)3 + I2 + H2O + Na2SO4 + K2SO4
  5. Chemistry

    1) Balance this redox reaction using the oxidation-number method. Zn + O2 + HCl ® ZnCl2 + H2O 2) Balance this redox reaction using the half-reaction method. (basic solution) Zn + MnO4- ® Zn(OH)2 + MnO2
  6. Chemistry

    I know nothing about chemistry, but am wondering if someone could help me with these. 1) Balance this redox reaction using the oxidation-number method. Zn + O2 + HCl ® ZnCl2 + H2O 2) Balance this redox reaction using the half-reaction …
  7. chemistry

    Balance each of the following redox equations using the half-reaction method. HI(s) + H2SO4 (aq) --> H2S(g) + I2 (s) My only question about this equation is...how do I know how many electrons I need to put on both sides?
  8. chemistry

    balance H2SO4 + NaOH --> H2O + Na2SO4
  9. General Chemistry

    Balance the following redox reaction in acidic and basic solutions: Fe(OH)2(s) + O2(g) --> Fe(OH)3(s) These are the steps my instructor gave us to balance redox reactions: 1. Divide into 1/2 rxns (reduction & oxidation) 2. Balance …
  10. Chemistry

    Complete and balance the equation for this reaction in basic solution?

More Similar Questions