Redox reactins play a pivoted role in chemistry and biology. The values of standard redox potential `(E^(@))` of two half-cell reactions decide which way the reaction is expected to proceed. A simple example is a Daniel cell in which zinc goes into solution and copper gets deposited. Given below is a set of half-cell reactions (acidic medium) along with their `E^(@)` values with respect to normal hydrogen electrode. Using this data, obtained the correct explanations to questions `15-16`
`I_(2)+2e^(-)to2I^(-),E^(@)=1.36V`
`Mn^(3+)+e^(-)toMn^(2+),E^(@)=1.50V`
`Fe^(3+)+e^(-)toFe^(2+),E^(@)=0.77V`
`O_(2)+4H^(+)+4e^(-)to2H_(2)O,E^(@)=1.23V`
Q. Electrolysis of dilute aqueous `NaCl` solution was carried out by passing 10 milliampere current. The time required to liberate 0.01 mole of `H_(2)` gas at the cathode is: (1 faraday `=96500C`)
A. `9.65xx10^(4)sec`
B. `19.3xx10^(4)sec`
C. `28.95xx10^(4)sec`
D. `38.6xx10^(4)sec`


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Correct Answer - B
Faraday law equivalents of `H_(2)` produced `=(Ixxt(sec))/(96500)`
`0.01xx2=(10xx10^(3)xxt)/(96500)=96500xx2=t`
`19.3xx10^(3)sec=t`