Question 21.3: Using Table 17.1, decide whether hydrogen peroxide will reac...
Using Table 17.1, decide whether hydrogen peroxide will react with (oxidize or reduce) the following ions in acid solution at standard concentrations:
I^-, Sn^{2+}, and Co^{2+}
STRATEGY
1. Since H_2O_2 disproportionates, it can either be reduced (and oxidize the ions) or be oxidized (and reduce the ions).
2. For a redox reaction to occur where H_2O_2 is reduced,
E^{\circ}_{red} H_2O_2(1.763 V) + E^{\circ}_{ox} ion > 0
3. For a redox reaction to occur where H_2O_2 is oxidized,
E^{\circ}_{ox} H_2O_2(-0.695 V) + E^{\circ}_{red} ion > 0
Table 17.1 Standard Potentials in Water Solution at 25°C | ||||
Acidic Solution, [H^+] = 1 M | ||||
{E^{\circ}}_{red} (V) | ||||
Li^+(aq) + e^- | \longrightarrow Li(s)\blacktriangleleft ⓘ | -3.04 | ||
K^+(aq) + e^- | \longrightarrow K(s) | -2.936 | ||
Ba^{2+}(aq) + 2e^{-} | \longrightarrow Ba(s) | -2.906 | ||
Ca^{2+}(aq) + 2e^- | \longrightarrow Ca(s) | -2.869 | ||
Na^+(aq) + e^- | \longrightarrow Na(s) | -2.714 | ||
Mg^{2+}(aq) + 2e^- | \longrightarrow Mg(s) | -2.357 | ||
Al^{3+}(aq) + 3e^- | \longrightarrow Al(s) | -1.68 | ||
Mn^{2+}(aq) + 2e^- | \longrightarrow Mn(s) | -1.182 | ||
Zn^{2+}(aq) + 2e^- | \longrightarrow Zn(s) | -0.762 | ||
Cr^{3+}(aq) + 3e^- | \longrightarrow Cr(s) | -0.744 | ||
Fe^{2+}(aq) + 2e^- | \longrightarrow Fe(s) | -0.409 | ||
Cr^{3+}(aq) + e^- | \longrightarrow Cr^{2+}(aq) | -0.408 | ||
Cd^{2+}(aq) + 2e^- | \longrightarrow Cd(s) | -0.402 | ||
PbSO_4(s) + 2e^- | \longrightarrow Pb(s) + {SO_4}^{2-}(aq) | -0.356 | ||
Tl^+(aq) + e^- | \longrightarrow Tl(s) | -0.336 | ||
Co^{2+}(aq) + 2e^- | \longrightarrow Co(s) | -0.282 | ||
Ni^{2+}(aq) + 2e^- | \longrightarrow Ni(s) | -0.236 | ||
AgI(s) + e^- | \longrightarrow Ag(s) + I^-(aq) | -0.152 | ||
Sn^{2+}(aq) + 2e^- | \longrightarrow Sn(s) | -0.141 | ||
Pb^{2+}(aq) + 2e^- | \longrightarrow Pb(s) | -0.127 | ||
2H^+(aq) + 2e^- | \longrightarrow H_2(g) | 0 | ||
AgBr(s) + e^- | \longrightarrow Ag(s) + Br^-(aq) | 0.073 | ||
S(s) + 2H^+(aq) + 2e^- | \longrightarrow H_2S(aq) | 0.144 | ||
Sn^{4+}(aq) + 2e^- | \longrightarrow Sn^{2+}(aq) | 0.154 | ||
{SO_4}^{2-}(aq) + 4H^+(aq) + 2e^- | \longrightarrow SO_2(g)+ 2H_2O | 0.155 | ||
Cu^{2+}(aq) + e^- | \longrightarrow Cu^+(aq) | 0.161 | ||
Cu^{2+}(aq) + 2e^- | \longrightarrow Cu(s) | 0.339 | ||
Cu^+(aq) + e^- | \longrightarrow Cu(s) | 0.518 | ||
I_2(s) + 2e^- | \longrightarrow 2I^-(aq) | 0.534 | ||
Fe^{3+}(aq) + e^- | \longrightarrow Fe^{2+}(aq) | 0.769 | ||
{Hg_2}^{2+}(aq) + 2e^- | \longrightarrow 2Hg(l) | 0.796 | ||
Ag^+(aq) + e^- | \longrightarrow Ag(s) | 0.799 | ||
2Hg^{2+}(aq) + 2e^- | \longrightarrow {Hg_{2}}^{2+}(aq) | 0.908 | ||
{NO_3}^-(aq) + 4H^+(aq) + 3e^- | \longrightarrow NO(g) + 2H_2O | 0.964 | ||
{AuCl_4}^-(aq) + 3e^- | \longrightarrow Au(s) + 4Cl^-(aq) | 1.001 | ||
Br_2(l) + 2e^- | \longrightarrow 2Br^-(aq) | 1.077 | ||
O_2(g) + 4H^+(aq) + 4e^- | \longrightarrow 2H_2O | 1.229 | ||
MnO_2(s) + 4H^+(aq) + 2e^- | \longrightarrow Mn^{2+}(aq) + 2H_2O | 1.229 | ||
{Cr_2O_7}^{2-}(aq) + 14H^+(aq) + 6e^- | \longrightarrow 2Cr^{3+}(aq) + 7H_2O | 1.33 | ||
Cl_2(g) + 2e^- | \longrightarrow 2Cl^-(aq) | 1.36 | ||
{ClO_3}^{-}(aq) + 6H^+(aq) + 5e^- | \longrightarrow \frac{1}{2} Cl_2(g) + 3H_2O | 1.458 | ||
Au^{3+}(aq) + 3e^- | \longrightarrow Au(s) | 1.498 | ||
{MnO_4}^{-}(aq) + 8H^+(aq) + 5e^- | \longrightarrow Mn^{2+}(aq) + 4H_2O | 1.512 | ||
PbO_2(s) + {SO_4}^{2-}(aq) + 4H^+(aq) + 2e^- | \longrightarrow PbSO_4(s) + 2H_2O | 1.687 | ||
H_2O_2(aq) + 2H^+(aq) + 2e^- | \longrightarrow 2H_2O | 1.763 | ||
Co^{3+}(aq) + e^- | \longrightarrow Co^{2+}(aq) | 1.953 | ||
F_2(g) + 2e^- \blacktriangleleft ⓘ | \longrightarrow 2F^-(aq) | 2.889 | ||
Basic Solution, [OH^-] = 1 M | ||||
{E^{\circ}}_{red} (V) | ||||
Fe(OH)_2(s) + 2e^- | \longrightarrow Fe(s) + 2OH^-(aq) | -0.891 | ||
2H_2O + 2e^- | \longrightarrow H_2(g) + 2OH^-(aq) | -0.828 | ||
Fe(OH)_3(s) + e^- | \longrightarrow Fe(OH)_2(s) + OH^-(aq) | -0.547 | ||
S(s) + 2e^- | \longrightarrow S^{2-}(aq) | -0.445 | ||
{NO_3}^{-}(aq) + 2H_2O + 3e^- | \longrightarrow NO(g) + 4OH^-(aq) | -0.14 | ||
{NO_3}^-(aq) + H_2O + 2e^- | \longrightarrow {NO_2}^-(aq) + 2OH^-(aq) | 0.004 | ||
{ClO_4}^-(aq) + H_2O + 2e^- | \longrightarrow {ClO_3}^-(aq) + 2OH^-(aq) | 0.398 | ||
O_2(g) + 2H_2O + 4e^- | \longrightarrow 4OH^-(aq) | 0.401 | ||
{ClO_3}^-(aq) + 3H_2O + 6e^- | \longrightarrow Cl^-(aq) + 6OH^-(aq) | 0.614 | ||
ClO^-(aq) + H_2O + 2e^- | \longrightarrow Cl^-(aq) + 2OH^-(aq) | 0.89 |
ⓘ Lithium is the strongest reducing agent.
ⓘ Lithium and fluorine are very dangerous materials to work with.
ⓘ O= strongest oxidizing agent;
R = strongest reducing agent.
ⓘ Fluorine is the strongest oxidizing agent.
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