Question

38. The following redox half reactions are combined in a voltaic cell. Which reaction occurs at the cathode and what is the Eceu? Fe2+(aq) + 2e → Fe(s) E°=-0.44 V Cu²+(aq) + 2e → Cu(s) E°= 0.34 V a) b) c) d) Cu2+(aq) + 2e → Cu(s), Ecell = 0.78 V Fe2+(aq) + 2e → Fe(s), Ecel = 0.78 V Fe2+(aq) + 2e → Fe(s), Ecell =-0.10 V Cu²+(aq) + 2e → Cu(s), Ecel = 0.10 V Cu²+ (aq) + 2e → Cu(s), Ecell = -0.78 V 39. What is the Ecell at 25°C for the following reaction and is it spontaneous? Cd(s) + Cd2+ (aq, 10-4 mol L-?) → Cd2+ (aq, 0.1 mol L-1) + Cd(s) Cd2+(aq) + 2e → Cd(s) E°= -0.40 V a) 0.09 V, Spontaneous OV, Spontaneous -0.09 V, Not spontaneous 0V, Not spontaneous 0.80 V, Spontaneous d)

Answer 1

36) Feedest dé → fece e-coton V Cum est Qe - Cucon = 0.34 v reduction of fe has the lower value, so fe is the anode and Cu in the cathode. É cell = 0.34-(-0.44) F 0.79 v reduction at caltode, cuies undergoes reduction a) Cuestae - Cucess Ecell = 0.78 v 89) cdao+cado el 16 Finale) - col cool molle) 4 edes ) Eceli = Ecell - 0.0592_10gQ -0.40-(0-0592) 105CO00) E-0-4888 V Ecell is negative, reaction is non spontaneous