Question

The electrolyte in lead storage battery is dilute sulpguric acid. The concentration of sulphuric acid in a lead-storage battery must be between $4.8\, M$ and $5.3\, M$ for most efficient functioning. A $5\, mL$ sulphuric acid sample of a particular battery requires $50\, mL$ of $1.0 \,M$ $NaOH$ for complete neutralisation. Which of the following statements about the functioning of battery is the most appropriate?

• A. The acid concentration in the battery is not in the most effective range
• B. The add concentration in the battery is in the most effective range
• C. The add concentration in the battery is hardly in the most effective range
• D. Only a good mechanic can tell whether or not the add concentration in the battery is in the most effective range

Answer 1

Answer: (B)

Volume of sample of sulphuric acid $=5 mL$ Volume of $NaOH$ required for neutralisation $=50 mL$

Normality of $NaOH$ required for neutralisation

$=1.0 M =1.0\,N$

Normality of sample of sulphuric acid $=?$

$\because \,\,\,\, N_{1} V_{1}=N_{2} V_{2}$

$N_{1} =\frac{1.0 \times 50}{5}=10 N $

$\therefore $ Molarity = $\frac{\text { normality }}{\text { valence }} = \frac{10}{2}=5 M$

Thus, the acid concentration in lead storage battery is in the most effective range (ie, between $4.8$ and $5.3 M$ ).