Question

Use the References to access important values if needed for this question. Enter electrons as e Use smallest possible integer coefficients. States are not required. If a box is not needed, leave it blank. Standard Reduction Potentials (Volts) at 25 °C I2 (s)+2 e>21 (aq) 0.535 0,(g)+4H,0'(aq)+4e >6H.00) 1.229 2 H20(0)+2e>H2(g) + 2 OH(aq) -0.828 -0.905 Cr2* (aq)+2 eCr (s) A 0.195 M neutral aqueous Cr12 solution is electrolyzed under 1 atm pressure using platinum electrodes. (a) Write the half-reactions expected to occur, taking into account the effect of the non-standard conditions on the electrode potentials. Half-reaction at anode Half-reaction at cathode Previous Next (b) What is the expected decomposition potential?

Answer 1

for the electrolysis of CrI2

a) half - cell reaction at the anode ( oxidation will happen)

2 I^- + 6 H2O ----> I2 + O2 + 4H3O+ + 6 e-

half-cell reaction at cathde ( reduction will happen)

Cr2+ + 4H2O + 6 e- ----> Cr + 2H2 + 4OH-

b) expected decomposition potential = - 2.057 V

E(cathode) - E(anode ) = -0.828 - 1.229 = - 2.057 V