In a lead storage battery, the anode reaction is, $P b + H_{2} S O_{4} \to P b S O_{4} + 2 H^{+} + 2 e^{-}$
Weight in g of Pb would be used up for battery to use for 1 ampere hour is___________. (write the nearest integer value)

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Solution

The current passed is 100 ampere hour.
The number of Faradays passed is $\frac{I (A) \times t (s)}{96500} = \frac{1 \times 3600}{96500} = 3.73 \times 10^{- 2}$ .
$1$ mole of $P b$ will be deposited by $2$ Faradays of electricity.
The molar mass of $P b$ is $207$ g/mol.
The mass of lead deposited is $\frac{3.73 \times 10^{- 2} \times 207}{2} = 3.86 g \approx 4$ .

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Q. During the discharge of a lead storage battery the density of sulphuric acid fell from

1.294

1.139 {g mL}^{- 1}

H_{2} S O_{4}

of density

1.294 {g mL}^{- 1}

is 39% and that of density

1.139 {g mL}^{- 1}

is 20% by weight. The battery holds

3.5 L

of acid and the volume practically remains constant during the discharge. Calculate the number of Ampere hours for which the battery must have been used. The discharging reactions are:

P b + S O_{4}^{2 -} \to P b S O_{4} + 2 e^{-} (anode)

P b O_{2} + 4 H^{+} + S O_{4}^{2 -} + 2 e^{-} \to P b S O_{4} + 2 H_{2} O (cathode)

Q. During the discharge of a lead storage battery, the density of sulphuric acid fell from 1.294 to 1.139

g m L^{- 1}

H_{2} S O_{4}

of density

1.294 g m L^{- 1}

is 39% and that of density

1.139 g m L^{- 1}

is 20% by weight.The battery holds 3.5 L of acid and the volume practically remains constant during discharge. The number of ampere hours for which the battery must have been used are........................
The discharging and charging reactions are:

P b + S O_{4}^{2 -} \to P b S O_{4} + 2 e^{-}

(charging)

P b O_{2} + 4 H^{+} + S O_{4}^{2 -} + 2 e^{-} \to P b S O_{4} + 2 H_{2} O

(discharging)

During the discharge of a lead storage battery, the density of sulphuric acid fell from $1.294$ to $1.139$ gm $L^{- 1}$ . Sulphuric acid of density $1.294$ gm $L^{- 1}$ is $39$ % by weight and that of density 1.139 gm $L^{- 1}$ is $20$ % by weight. The battery holds $3.5$ litres of acid and the column practically remained constant during the discharge.