Question

Calculate the equivalent weight of Sulfuric acid. $\left( {H = 1,S = 32,O = 16} \right)$

A.$39u$
B.$44u$
C.$49u$
D.$98u$

Answer 1

Equivalent weight of a compound is equal to molecular weight divided by number of replaceable hydrogen ion or hydroxide ion (hydrogen ion of acids and hydroxide ions for bases). First find the molecular weight of sulfuric acid and then divide it by the number of replaceable hydrogen ions as sulfuric acid is an acid.

Complete step by step answer:
We know that the chemical formula of sulfuric acid is ${H_2}S{O_4}$.
Given masses are $H = 1$, $S = 32$ and $O = 16$.
Then molar weight of sulfuric acid is given by

Molar Weight= 2+32+64=98u
${\text{Molar weight}} = 2 \times 1 + 1 \times 32 + 4 \times 16$
Equivalent weight of a sulfuric acid is equal to the molar weight of sulfuric acid divided by the number of replaceable hydrogen ions in sulfuric in aqueous solution. And we know that there are two replaceable hydrogen in it. Then its equivalent weight is given by
${\text{Equivalent weight = }}\dfrac{{{\text{Molar weight}}}}{{{\text{Number of replaceable H}}}}$
${\text{Equivalent weight}} = \dfrac{{98}}{2} = 49u$.
Then the molar weight of sulfuric acid is $98u$ and have two replaceable hydrogen then its equivalent weight is $49u$.

Hence the correct answer is option C.

Note: Here we use the atomic mass unit $\left( u \right)$ as a unit of weight which is equal to mass of a single proton. These replaceable hydrogens are replaced when we react acid with bases and we get salt after replacing these hydrogen and hydroxide ions in aqueous solution. Sulfuric or sulphuric acid are the same but sulfuric is American and sulphuric is a British word.