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प्रश्न
Write cathode and anode reaction in a fuel cell.
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उत्तर
Cell reactions in a fuel cell:
Oxidation at the anode (-):
Oxidation of hydrogen gas to water occurs at the anode.
2H2(g) + 4OH-(aq) →4H2O(l) + 4e-
Reduction at the cathode (+):
Reduction of oxygen gas to OH ions occurs at the cathode.
O2(g) + 2H2O(l) + 4e- → 4OH-(aq)
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संबंधित प्रश्न
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\[\ce{M | M+ || X- | X}\];
\[\ce{E^{\circ}_{{M^{+}/{M}}}}\] = 0.44 V,
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Which of the following is TRUE for this data?
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`"E"_("Cr"_2"O"_7^(2-)//"Cr"^(3+))^⊖`= 1.33 V `"E"_("Cl"_2//"Cl"^-)^⊖` = 1.36 V
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Oxidation-reduction reactions are commonly known as redox reactions. They involve transfer of electrons from one species to another. In a spontaneous reaction, energy is released which can be used to do useful work. The reaction is split into two half-reactions. Two different containers are used and a wire is used to drive the electrons from one side to the other and a Voltaic/Galvanic cell is created. It is an electrochemical cell that uses spontaneous redox reactions to generate electricity. A salt bridge also connects to the half-cells. The reading of the voltmeter gives the cell voltage or cell potential or electromotive force. If \[\ce{E^0_{cell}}\] is positive the reaction is spontaneous and if it is negative the reaction is non-spontaneous and is referred to as electrolytic cell. Electrolysis refers to the decomposition of a substance by an electric current. One mole of electric charge when passed through a cell will discharge half a mole of a divalent metal ion such as Cu2+. This was first formulated by Faraday in the form of laws of electrolysis.
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- When does electrochemical cell behaves like an electrolytic cell? (1)
- (i) What will happen to the concentration of Zn2+ and Ag+ when Ecell = 0. (1)
(ii) Why does conductivity of a solution decreases with dilution? (1)
OR
The molar conductivity of a 1.5 M solution of an electrolyte is found to be 138.9 S cm2mol-1. Calculate the conductivity of this solution. (2)
On which electrode the oxidation reaction takes place?
Which of the following is incorrect?
In a solution of CuSO4, how much time will be required to precipitate 2 g copper by 0.5 ampere current?
The number of moles of electrons passed when the current of 2 A is passed through a solution of electrolyte for 20 minutes is ______.
Can we construct an electrochemical cell with two half-cells composed of ZnSO4 solution and zinc electrodes? Explain your answer.
Explain why the anode is of negative polarity in a galvanic cell.
What is an electrochemical cell? What does it consist of?
What are electrochemical reactions?
Explain the types of electrochemical cells.
