${{m}_{dd\text{ t }\!\!\ddot{\ }\!\!\text{ ng}}}=65{{n}_{Zn(p\text{ v }\!\!\acute{\mathrm{i}}\!\!\text{ i F}{{\text{e}}^{3+}})}}+{{n}_{Zn(\text{p v }\!\!\acute{\mathrm{i}}\!\!\text{ i F}{{\text{e}}^{2+}})}}.\Delta {{M}_{Zn-Fe}}\Rightarrow {{n}_{Zn(p\text{ v }\!\!\acute{\mathrm{i}}\!\!\text{ i F}{{\text{e}}^{2+}})}}=0,2\ mol$$\Rightarrow \sum{{{n}_{Zn(p)}}=}{{n}_{Zn(p\text{ v }\!\!\acute{\mathrm{i}}\!\!\text{ i F}{{\text{e}}^{3+}})}}+{{n}_{Zn(\text{p v }\!\!\acute{\mathrm{i}}\!\!\text{ i F}{{\text{e}}^{2+}})}}=0,12+0,2=0,32\Rightarrow {{m}_{Zn}}=$ 20,8(g)