Solutions Question 369
Question: If $ \alpha $ is the degree of dissociation of $ Na_2SO_4 $ , the vant Hoff’s factor (i) used for calculating the molecular mass is
Options:
A) $ 1+\alpha $
B) $ 1-\alpha $
C) $ 1+2\alpha $
D) $ 1-2\alpha $
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Answer:
Correct Answer: C
Solution:
$ \begin{aligned} & \begin{matrix} {} & {} & {} & \begin{matrix} {} & {} & {} & \begin{matrix} {} & \begin{matrix} {} & \begin{matrix} {} & Na_2SO_4\xrightarrow{{}}2N{a^{+}}+SO_4^{2-} \\ \end{matrix} \\ \end{matrix} \\ \end{matrix} \\ \end{matrix} \\ \end{matrix} \\ & \begin{matrix} Mol\text{. before}dissociation & 1 & {} & \begin{matrix} {} & {} & 0 & \begin{matrix} {} & 0 \\ \end{matrix} \\ \end{matrix} \\ \end{matrix} \\ & \begin{matrix} Mol\text{. after}dissociation & 1-\alpha & {} & \begin{matrix} {} & 2\alpha & {} & 1\alpha \\ \end{matrix} \\ \end{matrix} \\ \end{aligned} $
$ i=1-\alpha +2\alpha +\alpha =1+2\alpha $
