Skip to content
Choose the Best Answer · Q16

Q.In the H2-O2\text{H}_2\text{-O}_2 fuel cell, the reaction that occurs at the cathode is

(a) O2(g)+2H2O(l)+4e−→4OH−(aq)\text{O}_2\text{(g)} + 2\text{H}_2\text{O(l)} + 4e^{-} \rightarrow 4\text{OH}^{-}\text{(aq)}
(b) H+(aq)+OH−(aq)→H2O(l)\text{H}^{+}\text{(aq)} + \text{OH}^{-}\text{(aq)} \rightarrow \text{H}_2\text{O(l)}
(c) 2H2(g)+O2(g)→2H2O(g)2\text{H}_2\text{(g)} + \text{O}_2\text{(g)} \rightarrow 2\text{H}_2\text{O(g)}
(d) H++e−→12H2\text{H}^{+} + e^{-} \rightarrow \dfrac{1}{2}\text{H}_2
Puducherry TnboardTextbookSubjectiveImportance★★★★★est
42% · 31/73 Questions
🔒 Locked · start free trial →

You're viewing a preview — the full solution, concept, methods & PYQ mapping are locked.

Start your 14-day free trial to unlock the full solution →

Step 1. In the hydrogen-oxygen fuel cell, oxidation of H₂ occurs at the anode and reduction of O₂ occurs at the cathode — recall the two half-reactions exactly as stated in the fuel cells section.

Step 2. The cathode (reduction) half-reaction is O2(g)+2H2O(l)+4e−→4OH−(aq)\text{O}_2\text{(g)} + 2\text{H}_2\text{O(l)} + 4e^{-} \rightarrow 4\text{OH}^{-}\text{(aq)} — oxygen gains 4 electrons per molecule and combines with water to regenerate hydroxide ions in the alkaline KOH electrolyte. …

Start your 14-day free trial to unlock the full solution →

Unlock everything free for 14 days

  • Full step-by-step solutions
  • Concept-first explanations
  • Methods, shortcuts & mistakes
  • PYQ mapping + timed mock tests
Start 14-day free trial →See Plans & Pricing →

Full access for 14 days. No credit card required.

←Previous question · evaluationQ15 — Assertion: Pure iron, when heated in dry air, is converted to a layer …→Next question · evaluationQ17 — The equivalent conductance of a M/36 solution of a weak monobasic acid…