Question

molecular weight of dibasic acid is W. Its equivalent weight will be :
1) W/2
2) W/3
3) W
4) 3W

Answer 1

Answer: The correct answer is Option 1.

Explanation:

Equivalent weight of an acid or base is defined as the ratio of their molecular weight and their basicity or acidity respectively.

Mathematically,

$\text{Equivalent weight of acid}=\frac{\text{Molecular weight}}{\text{Basicity}}$

We are given;

Molecular weight of acid = W

And the given acid is a dibasic acid, thus it will have a basicity of 2.

Putting values in above equation, we get:

$\text{Equivalent weight of acid}=\frac{W}{2}$

Hence, the correct answer is Option 1.

Answer 2

Answer:

The equivalent weight of the dibasic acid is $\bold{\frac{W}{2}}$.  

Explanation:

A dibasic acid can be defined as the acid that can give two hydrogen ions in its solution. It other words we can say that one molecule of a dibasic acid always gives two hydrogen ions.

Hence it can be shown as:

$\bold{\mathrm{H}_{2} \mathrm{A} \rightarrow 2 \mathrm{H}^{+}+\mathrm{A}^{-}}$

If we consider the molecular weight of dibasic acid as W, the equivalent weight must be $\bold{\frac{W}{2}}$ as it can give two hydrogen ions.