Under standard conditions for all concentrations, the following reactions is spontaneous at 25^@C O_2(g)+4H^+ (aq)+4Br^(-) (aq) to 2H_2O (l) +2Br_2 (l), E^@=0.16V IF [H^+] is adjusted by adding a buffer of 0.10 M NaOCN and 0.10 M HOCN (K_a=3.5 times 10^-4) what value will E_(cell) have and will the reaction be spontaneous at this [H^+]?

Under standard conditions for all concentrations, the following reacti

1.	Under standard conditions for all concentrations, the following reactions is spontaneous at 25^@C O_2(g)+4H^+ (aq)+4Br^(-) (aq) to 2H_2O (l) +2Br_2 (l), E^@=0.16V IF [H^+] is adjusted by adding a buffer of 0.10 M NaOCN and 0.10 M HOCN (K_a=3.5 times 10^-4) what value will E_(cell) have and will the reaction be spontaneous at this [H^+]?
Answer» SOLUTION :For a buffer solution of HOCN and NaOCN we have `[H^+]=K_a TIMES ([HOCN])/([NaOCN]) =3.5 times 10^-4 times 0.1/0.1=3.5 times 10^-4` THUS, `E_(cell)=E_(cell)^@-0.0591/4 log""1/([H^+]^4[Br^-]^4)` `=0.16-0.0591/4 log ""1/((3.5 times 10^-4)^4 (1.0)^4)` `=-0.044V` Negative VALUE of `E_(cell)` suggests that the GIVEN cell reaction is nonspontaneous when `[H^+]` is adjusted by a buffer solution.