Chem201A
Dr. Lara Baxley
Oxidation-Reduction Worksheet
1. Assign oxidation numbers to each atom in the following:
a. P4O6
b. BiO3−
c. N2H4
d. Mg(BrO4)2
e. MnSO4
f. Mn(SO4)2
2. For each of the reactions below identify the oxidizing agent and the reducing agent.
a. 2 KCl + MnO2 + H2SO4 → K2SO4 + MnSO4 + Cl2 + H2O
b. SiCl4 + 2 Mg(s) → 2 MgCl2 + Si
c. 2 Na2S2O3 + 2 HNO3 + KOCl  Na2S4O6 + KCl + H2O + NaNO3
3. Using the activity series given in the Chapter 4 Notes, determine whether each of the
following combinations will react. If the do not react, write NR after the arrow. If they do
react, write the products including states and balance the equation.
a. _____ Mn(s) + _____ CrCl3(aq) →
b. _____ Pb(s) + _____ HNO3(aq) →
c. _____ Sn(s) + _____ Mg(ClO4)2(aq) →
d. _____ ZnSO4(aq) + _____ Al(s) →
Chem201A
Dr. Lara Baxley
Answers
1. a. O −2, P +3
d. Mg +2, O −2, Br +7
b. O −2, Bi +5
c. H +1, N -2
e. Mn +2, O −2, S +6
f. Mn +4, O −2, S +6
Hint: On these ionic compounds, separate them into the ions first. For example, for MnSO4,
I separated into Mn2+ + SO42−. That way, I can figure out the charge on Mn, and it’s now
easier to find the oxidation number of S.
2. a. Reducing Agent: KCl, Oxidizing Agent: MnO2
b. Reducing Agent: Mg, Oxidizing Agent: SiCl4
c. Reducing Agent: Na2S2O3, Oxidizing Agent: KOCl
3.
a. __3__ Mn(s) + __2__ CrCl3(aq) → 3 MnCl2(aq) + 2 Cr(s)
b. _____ Pb(s) + __2__ HNO3(aq) → Pb(NO3)2(aq) + H2(g)
c. _____ Sn(s) + _____ Mg(ClO4)2(aq) → NR (Sn is below Mg in Activity Series)
d. __3__ ZnSO4(aq) + __2__ Al(s) → 3 Zn(s) + Al2(SO4)3(aq)