Metal strips are immersed in aqueous solutions of various salts. In which combinations do you expect a spontaneous redox reaction: (a) Silver strip in \(\operatorname{CuBr}_{2}(a q)\) (b) Copper strip in \(\mathrm{ZnSO}_{4}(a q)\) (c) Zinc strip in \(\operatorname{AgNO}_{3}(a q)\) (d) Gold strip in \(\mathrm{FeCl}_{2}(a q)\) (e) Copper strip in \(\mathrm{Hg}\left(\mathrm{NO}_{3}\right)_{2}(a q)\)

First, we need to identify the metals and metal ions in the problem. (a) Silver strip in CuBr2(aq) - Metal: Silver(Ag); Ion: Copper(II) (Cu²⁺) (b) Copper strip in ZnSO4(aq) - Metal: Copper(Cu); Ion: Zinc(II) (Zn²⁺) (c) Zinc strip in AgNO3(aq) - Metal: Zinc(Zn); Ion: Silver(I) (Ag⁺) (d) Gold strip in FeCl2(aq) - Metal: Gold(Au); Ion: Iron(II) (Fe²⁺) (e) Copper strip in Hg(NO3)2(aq) - Metal: Copper(Cu); Ion: Mercury(II) (Hg²⁺)

Next, we need to compare the reactivity of each given metal strip and the metal ion in the solution using the electrochemical series chart. Recall that if the metal strip is higher in the chart than the ion, a reaction will occur spontaneously. We will use the following list of standard electrode potentials (in V) for this purpose: Ag⁺/Ag = +0.80 Cu²⁺/Cu = +0.34 Zn²⁺/Zn = -0.76 Au³⁺/Au = +1.50 Hg²⁺/Hg = +0.79 Now let's compare the metals to the ions in their respective combinations:

(a) Silver strip in CuBr₂(aq): Ag⁺/Ag (+0.80) vs Cu²+/Cu(+0.34) Since Silver(Ag) is higher in the chart than Copper(Cu), no reaction will occur. (b) Copper strip in ZnSO₄(aq): Cu²⁺/Cu (+0.34) vs Zn²+/Zn(-0.76) Since Copper(Cu) is lower in the chart than Zinc(Zn), a spontaneous reaction will occur. (c) Zinc strip in AgNO₃(aq): Zn²⁺/Zn (-0.76) vs Ag⁺/Ag (+0.80) Since Zinc(Zn) is higher in the chart than Silver(Ag), a spontaneous reaction will occur. (d) Gold strip in FeCl₂(aq): Au³⁺/Au(+1.50) vs Fe²⁺/Fe('unknown') Given that Gold(Au) has a high reduction potential, it is unlikely to react with Iron(II) (Fe). (e) Copper strip in Hg(NO₃)₂(aq): Cu²⁺/Cu(+0.34) vs Hg²⁺/Hg(+0.79) Since Copper(Cu) is lower in the chart than Mercury(Hg), a spontaneous reaction will occur.

After analyzing the combinations of metals and ions, we can conclude that spontaneous redox reactions will occur in the following combinations: (b) Copper strip in ZnSO₄(aq) (c) Zinc strip in AgNO₃(aq) (e) Copper strip in Hg(NO₃)₂(aq)