Indicate the reactions which take place at cathode and anode in fuel cell.

Explanation

(i) Oxiation at anode : At anode, hydrogen has is oxidised to `H_(2)O`.
`{:(2H_(2(g))+4OH_((aq))^(-)rarr 4H_(2)O_((1))+4e^(-)),(" (oxidation half reaction)"):}`
(ii) Reduction at cathode : The electrons released at anode travel to cathode through external circuit and reduce oxygen gas to `OH^(-)`.
`{:(O_(2(g))+2H_(2)O_((l))+4e^(-)rarr4OH_((aq))^(-)),(" (reduction half reaction)"):}`
(iii) Net cell reaction : Addition of both the above reactions at anode and cathode gives a net cell reaction.
`2H_(2(g))+O_(2(g))rarr 2H_(2)O_((l))" (overall cell reaction)"`