Question

The equivalent weight of acetic acid is?
\[
  A.{\text{ }}60u \\
  B.{\text{ }}120u \\
  C.{\text{ }}30u \\
  D.{\text{ }}40u \\
 \]

Answer 1

Hint- In order to find the equivalent weight of a given compound we will use the formula of equivalent weight as it is the ratio of molecular mass to the number of replaceable hydrogen. By the use of general formula and the atomic masses of elements from the periodic table we will solve this problem.

Complete answer:
Formula used- ${\text{Equivalent weight}} = \dfrac{{{\text{Molecular mass}}}}{{{\text{Number of replaceable H}}}}$
The molecular formula of acetic acid is $C{H_3}COOH$
As we know the atomic mass of hydrogen, carbon and oxygen from the periodic table is:
$H = 1u,C = 12u\& O = 16u$
So using the above atomic mass the molecular mass of $C{H_3}COOH$ is:
 $
   = \left( {4 \times {\text{Atomic mass of }}H} \right) + \left( {2 \times {\text{Atomic mass of }}C} \right) + \left( {2 \times {\text{Atomic mass of }}O} \right) \\
   = \left( {4 \times 1u} \right) + \left( {2 \times 12u} \right) + \left( {2 \times 16u} \right) \\
   = 4u + 24u + 32u \\
   = 60u \\
 $
We know the expression for the equivalent weight of an acid is as given as
${\text{Equivalent weight}} = \dfrac{{{\text{Molecular mass}}}}{{{\text{Number of replaceable H}}}}$
Acetic acid contains one replaceable hydrogen.
Substitute values in the above expression, we get
${\text{Equivalent weight}} = \dfrac{{60u}}{1} = 60u$

Hence, the equivalent weight of Acetic acid is 60u.

Note- Equivalent weight is the weight of one equivalent which is the weight of a given substance which combines with or displaces a fixed quantity of another. An element's equivalent weight is the mass which combines or displaces 1.008 grams of hydrogen. The main use of sulfuric acid is in fertilizer production, e.g., lime superphosphate and ammonium sulfate. It is commonly used even in the processing of chemicals and other acids.