Solutions Question 7
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 [AIEEE 2005]
Options:
A) $ 1+\alpha $
B) $ 1-\alpha $
C) $ 1+2\alpha $
D) $ 1-2\alpha $
Show Answer
Answer:
Correct Answer: C
Solution:
$ Na_2SO_4 $ -
$ 2N{a^{+}},+,SO _4^{2-} $
| Mol. before diss. | 1 | 0 | 0 |
|---|---|---|---|
| Mol. after diss | $ 1-\alpha $ | $ 2\alpha $ | $ 1\alpha $ |
$ i=\frac{Exp\text{.C}\text{.P}\text{.}}{Normal,C\text{.P}\text{.}}=1-\alpha +2\alpha +\alpha =1+2\alpha $
