Question

What is the equivalent weight of $\text{NaOH}$?

Answer 1

Step1. Equivalent weight

• The equivalent weight of the base is defined as the molecular mass of the base divided by the acidity of the base.

Step2. The formula for the equivalent weight

$\text{Equivalent weight of base=}\frac{\text{Molecular weight of base}}{\text{Acidity}}$

Step3. Equivalent weight of $\text{NaOH}$

• Molecular weight of $\mathrm{NaOH}$ (sodium hydroxide) is $40{\text{g mol}}^{-1}$.
• The dissociation of $\mathrm{NaOH}$ is as follows:-

$\mathrm{NaOH}\to {\mathrm{Na}}^{{}^{+}}+{\mathrm{OH}}^{{}^{-}}$

• So, the acidity of $\text{NaOH}$ is $1$.

$$\begin{gathered} \text{Equivalent weight of base=}\frac{{\text{40g mol}}^{-1}}{\text{Acidity}} \\ \text{=40 g}{\mathrm{mol}}^{-1} \\ =40{\text{g eq}}^{-1} \end{gathered}$$

Hence, the equivalent weight of $\text{NaOH}$ is $40{\text{g eq}}^{-1}$.