Write the cell reactions which occur in lead storage battery (i) when the battery is in use and (ii) when the battery is on charging.

Solution

(i) The cell reactions during the use (discharge) of lead storage battery are:

The cell reactions when the battery is in use are given below:

Anode: $P b (s) + S O_{4}^{2 -} (a q) \to P b S O_{4} + 2 e^{-}$

Cathode: ${PbO}_{2} (s) + 4 H^{+} (aq) + {SO}_{4}^{2 -} (aq) \to {PbSO}_{4} (s) + 2 H_{2} O (l)$

i.e., overall cell reaction consisting of cathode and anode reactions is:

$Pb (s) + {PbO}_{2} + 4 H^{+} (aq) + {SO}_{4}^{2 -} (aq) \to 2 {PbSO}_{4} (s) + 2 H_{2} O (l)$

ii) Recharging a lead-acid cell:

is a non-spontaneous redox reaction (E_(redox) is negative), that is, an electrolytic process
requires an input of slightly more than 2 volts per cell to drive the spontaneous reactions in the reverse direction
converts electrical energy back into chemical energy which is stored in the lead, lead dioxide and sulfuric acid in the cell

The cell reaction is:
At Anode:

{PbSO}_{4} (s) + 2 e^{-} \to Pb (s) + {SO}_{4}^{2 -} (aq) At Cathode : {PbO}_{2} (s) + 2 H_{2} O (l) \to {PbSO}_{4} + {SO}_{4}^{2 -} overall net reaction 2 {PbSO}_{4} (s) + 2 H_{2} O (l) \to Pb (s) + {PbO}_{2} (s) + 4 H^{+} (aq) + 2 {SO}_{4}^{2 -}

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Electrochemistry

Write the cell reactions which occur in lead storage battery (i) when the battery is in use and (ii) when the battery is on charging.

Some More Questions From Electrochemistry Chapter

How would you determine the standard electrode potential of the system Mg²⁺/Mg?

Can you store copper sulphate solutions in a Zinc pot?

Why does the conductivity of a solution decrease with dilution?

Suggest a way to determine the Λ°_m value of water.

The molar conductivity of 0.025 mol L^–1methanoic acid is 46.1 S cm² mol^–1. Calculate its degree of dissociation and dissociation constant. Give λ°(H⁺) = 349.6 S cm²mol^–1 and λ° (HCOO^– ) = 54.6 s cm² mol^–1.

If the current of 0.5 ampere flows through a metallic wire for 2 hours, then how many electrons flow through the wire?

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For Daily Free Study Material Join wiredfaculty

Electrochemistry

Write the cell reactions which occur in lead storage battery (i) when the battery is in use and (ii) when the battery is on charging.

Some More Questions From Electrochemistry Chapter

How would you determine the standard electrode potential of the system Mg2+/Mg?

Can you store copper sulphate solutions in a Zinc pot?

Why does the conductivity of a solution decrease with dilution?

Suggest a way to determine the Λ°m value of water.

The molar conductivity of 0.025 mol L–1 methanoic acid is 46.1 S cm2 mol–1. Calculate its degree of dissociation and dissociation constant. Give λ°(H+) = 349.6 S cm2 mol–1 and λ° (HCOO– ) = 54.6 s cm2 mol–1.

If the current of 0.5 ampere flows through a metallic wire for 2 hours, then how many electrons flow through the wire?

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

How would you determine the standard electrode potential of the system Mg²⁺/Mg?

Suggest a way to determine the Λ°_m value of water.

The molar conductivity of 0.025 mol L^–1methanoic acid is 46.1 S cm² mol^–1. Calculate its degree of dissociation and dissociation constant. Give λ°(H⁺) = 349.6 S cm²mol^–1 and λ° (HCOO^– ) = 54.6 s cm² mol^–1.