Question

Gram equivalent weight of sulphuric acid in the reaction involving Lead accumulator is:
A. 24.5g
B. 49g
C. 98g
D. 73.5g

Answer 1

Hint: The equivalent weight of an acid is the mass of that acid which is required to generate one mole of hydrogen. Using this formula we can solve the required problem.

Formula used: The formula for equivalent weight is:
$\text{Equivalent weight = }\dfrac{\text{molecular mass}}{\text{replaceable hydrogen or hydroxide ions}}\text{ }$

Step by step answer:
To find the equivalent weight of an acid, according to the general formula, we must divide molecular mass of that acid with the number of hydrogen/hydroxyl ions it replaces.
In this case, the molecular mass of sulphuric acid is 98 g/mol.
This is because the atomic mass of each atom summed up in sulphuric acid results in 98. The atomic mass of hydrogen = 1, and that of sulphur = 32, and of oxygen = 16.
$\therefore$molecular mass of ${{\text{H}}_{\text{2}}}\text{S}{{\text{O}}_{\text{4}}}\text{= 2 }\\!\\!\times\\!\\!\text{ H}\left( \text{At}\text{. No}\text{.} \right)\text{ + S}\left( \text{At}\text{. No}\text{.} \right)\text{ + 4 }\\!\\!\times\\!\\!\text{ O}\left( \text{At}\text{. No}\text{.} \right)$
$\text{= 2 }\\!\\!\times\\!\\!\text{ 1 + 32 + 4 }\\!\\!\times\\!\\!\text{ 16}$
$\text{= 98 g/mol}$
Now that we know the molecular mass of ${{\text{H}}_{\text{2}}}\text{S}{{\text{O}}_{\text{4}}}$,
We can put it into the general formula knowing that it replaces 2 hydrogen ions.
$\therefore \text{Equivalent weight = }\dfrac{\text{98}}{\text{2}}\text{ g}$
$\text{= 49 g}$
Therefore, we can conclude that the gram equivalent weight of sulphuric acid in the reaction involving Lead accumulator is 49 g. Hence, the answer is Option B.

Note: The equivalent weight of an acid is the mass of acid that is required to generate one mole of hydrogen ion or hydronium ion in an aqueous solution. If the acid or alkali contains more than one ionisable hydrogen ion or hydroxyl ion, the equivalent weight will be a fraction of its molar mass. But if it contains only 1 ionisable hydrogen or hydroxyl ion, it’s equivalent weight will be equal to its molar mass.