What are the fuel cells ? How are they different from galvanic cells ? Give the construction of `H_(2), O_(2)` fuel cell ?

What are the fuel cells ? How are they different from galvanic cells ?

1.	What are the fuel cells ? How are they different from galvanic cells ? Give the construction of `H_(2), O_(2)` fuel cell ?
Answer» A fuel cell is a galvanic cell in which the chenical energy of fuel-oxidant syste m is converted directly into electrical energy. `to` Convertional Galvanic cell converts chemical energy into electrical energy by spontaneous redox reactions. ` to` Fuel cell convert energy of combustion of fuels like hydrogen, meghane etc., into electrical energy. These cause less pollution,. `H_(2)-O_(2)` fuel cell: In this cell, hydrogen and oxygen are bubbled through porous carbon electrodes into Conc. NaOH solution. Electrodes are embedded with suitable catalysts. The electrode reactions are `O_(2(g))+2H_(2)O_((l))overset(+4e^(-))to4OH_((aq))^(-)` (Cathode) `2H_(2_((g)))+4OH_((aq))^(-) to4 H_(2)O_((l)) +4e^(-)` (anode) Overall reaction : `2H_(2_(g))+O_(2_(g))to 2H_(2) O_((l))` The cell function as long as the reacting gases are in supply. The hate of combustion is directly converted into electrical energy.

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Define molar conductivity of a solution and explain how molar conductivity changes with change in concentration of a solution for a weak and a strong electrolyte.
Limiting molar conductivity of `NH_(4)OH` [i.e., `Lambda_(m)^(@)(NH_(4)OH)`] is equal to:A. `Lambda_(m (NH_(4)Cl ))^(@) + Lambda_(m (NaCl))^(@) - Lambda_(m(NaOH))^(@)`B. `Lambda_(m (NaOH))^(@) + Lambda_(m(NaCl))^(@) - Lambda_(m(NH_(4)Cl))^(@)`C. `Lambda_(m(NH_(4)OH))^(@) + Lambda_(m (NH_(4)Cl))^(@) - Lambda_(m(HCl))^(@)`D. `Lambda_(m (NH_(4)Cl))^(@) + Lambda_(m (NaOH))^(@) - Lambda_(m(NaCl))^(@)`
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Based on the data given below, the correcy order of reducing power is: `Fe_((aq.))^(3+) + e rarr Fe_((aq.))^(2+), E^(@) = +0.77 V` `Al_((aq.))^(3+) + 3e rarr Al_((s)), E^(@) = -1.66 V` `Br_(2(aq.)) + 2e rarr 2Br_((aq.))^(-), E^(@) = +1.08 V`A. `Br^(-) lt Fe^(2+) lt Al`B. `Fe^(2+) lt Al lt Br^(-)`C. `Al lt Br^(-) lt Fe^(2+)`D. `Al lt Fe^(2+) lt Br^(-)`
Based on the data given below, the correcy order of reducing power is: `Fe_((aq.))^(3+) + e rarr Fe_((aq.))^(2+), E^(@) = +0.77 V` `Al_((aq.))^(3+) + 3e rarr Al_((s)), E^(@) = -1.66 V` `Br_(2(aq.)) + 2e rarr 2Br_((aq.))^(-), E^(@) = +1.08 V`A. `Br^(-) lt Fe^(2+) lt Al`B. `Fe^(2+) lt Al lt Br^-`C. `Al lt Br^(-) lt Fe^(2+)`D. `Al lt Fe^(2+) lt Br^(-)`
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What are the fuel cells ? How are they different from galvanic cells ? Give the construction of `H_(2), O_(2)` fuel cell ?

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