Question

Calculate the equivalent mass of ${H_2}S{O_4}$ from the given reactions.
(a) ${H_2}S{O_4} + NaOH \to NaHS{O_4} + {H_2}O$
(b) ${H_2}S{O_4} + 2NaOH \to N{a_2}S{O_4} + 2{H_2}O$
A.49 and 98
B.98 and 49
C.Both 49
D.Both 98

Answer 1

Equivalent mass of a substance can be explained as the number of parts by mass of the given chemical species which can combine with or displace 35.5 parts of Cl or 8.0 parts of O or 1.008 parts of H.

Complete Step-by-Step Answer:
Before we move forward with the solution of the given question, let us first understand some important basic concepts.
Depending on the type of the chemical species under consideration, the formula for calculating the equivalent mass can be varied. The basic formula for calculating the equivalent mass of any chemical species can be done by dividing the sum of the masses of the number of atoms of the given chemical species by the key characteristic property of that species.
Similarly, in the case of acids, it is its acidity and in the case of bases it is their basicity. The acidity of a compound can be explained as the number of replaceable hydrogen atoms in the given molecule of the acid. Similarly, basicity can be explained as the number of replaceable hydroxy groups in the molecular structure.
In the given question, we have been asked to find the equivalent mass of sulphuric acid. Since sulphuric acid is a strong acid, we would consider its acidity. The number of replaceable hydrogen atoms in ${H_2}S{O_4}$ is 1. Hence, we must divide the molecular mass of ${H_2}S{O_4}$ by 1. The molecular mass of ${H_2}S{O_4}$ is 98 g/mol.
Hence, the effective mass $= \left( {\dfrac{{98}}{1}} \right)$ = 98 in both the cases.

Hence, Option D is the correct option

Note: In case of elements, this characteristic is its valency. On the other hand, in case of a salt, we must consider the total positive or negative charge of the salt.