C-08-Q245mediumsingle_mcqCathode reaction in a dry cell:a2 NHX4X++2 MnOX2+2 eX−→2 NHX3+MnX2OX3+HX2O\ce{2NH4+ + 2MnO2 + 2e- -> 2NH3 + Mn2O3 + H2O}2NHX4X++2MnOXbHX++eX−→12 HX2\ce{H+ + e- -> 1/2 H2}HX++eXcZnX2++2 eX−→Zn\ce{Zn^2+ + 2e- -> Zn}ZnX2++2eXdCuX2++2 eX−→Cu\ce{Cu^2+ + 2e- -> Cu}CuX2++2eX