The two scientists set up their experimental apparatus by using following components.
(`CH_4`,`NH_3`,`H_2`, Condenser, Electrode, Vaccum pumps, boiling chambers, gas chambers, `U' shaped tubes)
state chemical evolution theory.

Which of the following statements are correct? Fuel cells are galvanic cells in which the chemical energy of fuel is directly converted into electrical energy. Type of fuel cell is a hydrogen - oxygen fuel cell. It consists of two electrodes made up of two porous graphite impregnated with a catalyst (platinum, silver, or metal oxide). The electrodes are placed in aqueous solution of NaOH. Oxygen nad hydrogen are continuously fed into the cell. Hydrogen gets oxidized to H^(oplus) which is neutralized by overset(Θ)(OH) , ie., anodic reaction. H_(2) hArr 2H^(oplus) + 2e^(-) 2H^(oplus) + 2 overset(Θ)(OH) hArr 2H_(2)O H_(2) + 2 overset(Θ)(OH) hArr 2H_(2)O + 2e^(-) At cathode, O_(2) gets reduced to overset(Θ)(OH) i.e., O_(2) + 2H_(2)O + 4e^(-) hArr overset(Θ)(4)OH Hence, the net reaction is 2H_(2) + O_(2) hArr 2H_(2)O The overall reaction has Delta H= -285.6kJ mol^(-1) and Delta G= -237.4kJ mol^(-1) " at " 25^(@)C A fuel cell is I. A voltaic cell in which continuous supply of fuels are sent at anode to perform oxidation II. A voltaic cell in which fuels such as CH_(4), H_(2) and CO are used up at anode. III. One which involves the reaction of H_(2)- O_(2) fuel cell such as: Anode 2H_(2) + 4 overset(Θ)(OH) rarr 4H_(2)O(I) + 4e^(-) cathode : O+ 2H_(2)O(I) + 4e^(-) rarr 4 overset(Θ)(OH) IV. The efficiency of H_(2)-O_(2) fuel cell is 70 to 75%