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Tollen reagent is used for the detection...

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 ?

A

`E_("oxi")` will increase by a factor of 0.65 from `E_(0" xi")^(@)`

B

`E_(oxi)` will decrease by a factor of 0.65 from `E_("oxi")^(@)`

C

`E_(red)` will increase by a factor of 0.65 from `E_(red)^(@)`

D

`E_(red)` will decrease by a factor of 0.65 from `E_(red)^(@)`.

Text Solution

Verified by Experts

The correct Answer is:
C
On increasing concentration of `NH_(3)`, the concentration of `H^(+)` ion decreases, therefore.
`E_(red)=E_(red)^(o)-(0.0592)/(n)log_(10)[H^(+)]^(2)`
`=0-(0.0592)/(2)xx2log_(10)10^(-11)`
`(becausepH=11,therefore[H^+]=10^(-11)M)`
`=0.0592xx11=0.6512V=0.65V`
`E_(red)` increased by a factor of 0.65 from `E_(red)^(o)`.
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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 ] Ammonia is always added in this reaction. Which of the followijng must be wrong ?

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 ] 2Ag^(o+)+C_(6)H^(12)O_(6)+H_(2)O rarr 2Ag^(s)+C_(6)H_(12)O_(7)+2H^(o+) Find lnK of this reaction.