Tollen reagent is used for the detection of aldehydes. When a solution of `AgNO_(3)` is added to glucose with `NH_(4)OH`, then gluconic acid is formed.
`Ag^(o+)+e^(-) rarr Ag," "E^(c-)._(red)=0.8V`
`C_(6)H_(12)O_(6)rarr underset(Gluconic aci d)(C_(6)H_(12)O_(7)+)2H^(o+)+2e^(-) , " "E^(c-)._(o x i d ) =-0.05V`
`[Ag(NH_(3))_(2)]^(o+)+e^(-) rarr Ag(s)+2NH_(3), " "E^(c-)._(red)=0.337V`
`[Use2.303xx(RT)/(F)=0.0592` and `(F)/(RT)=38.92at 298 K ]`
When ammonia is added to the solution, `pH` is raised to `11`. Which half cell reaction is affected by `pH` and by how much ?

Options

A. `NH_3` combines with `Ag^+` to from complex.
B. `Ag(NH_3)_2^+` is a weaker oxidising reagent than `Ag^+`
C. In absence of `NH_3` silver salt of gluconic acid is fromed.
D. `NH_3` has affected the standard reduction potential of glucose/gluconic acid electrode.

Answer

D