Question

The correct equation for the degree of association $'\alpha'$ of an associating solute, $'n'$ molecules of which undergoes association in solution, is

• A. $\alpha = \frac{n(i -1)}{ 1- n}$
• B. $\alpha = \frac{i(n -1)}{ 1 + n}$
• C. $\alpha = \frac{i( 1 + n)}{ 1- n}$
• D. $\alpha = \frac{i(n + 1)}{ 1- n}$
• E. $\alpha = \frac{n(1 - i)}{ 1- n}$

Answer 1

Answer: (A)

$n A \quad \Leftrightarrow A_{n}$

1 mole

$1-\alpha \quad \frac{\alpha}{n}, \quad$ Total $=1-\alpha+\frac{\alpha}{n}$

$\therefore i=1-\alpha+\frac{\alpha}{n}$ or $1-i=\alpha-\frac{\alpha}{n}=\alpha\left(1-\frac{1}{n}\right)$

$=\alpha\left(\frac{n-1}{n}\right)$

or $\alpha=\frac{n}{(n-1)}(i-i)=\frac{n(i-1)}{(1-n)}$