Question

There is KI and sucrose solution with 0.1 M concentration, if the osmotic pressure of KI and sucrose solution is 0.465 atm and 0.245 atm, respectively. The degree of dissociation of KI is

Answer 1

Given :

Osmotic pressure of KI solution = 0.465 atm

Osmotic pressure of sucrose solution = 0.245 atm

Molarity of the soution = 0.1M

To Find :

The degree of dissociation of KI

Solution :

• For KI solution

         $\pi =iCRT$

         $0.465 = i\times 0.1\times RT\rightarrow Equation(1)$

• For sucrose solution

         $\pi =CRT$

         $0.245 = 0.1\times RT\rightarrow Equation(2)$    

• By dividing equations 1 & 2

          $i=\frac{0.465}{0.245}$  

          $i=1.897$

• We also know the formula

          $\alpha =\frac{i-1}{n-1}$

          $\alpha =\frac{1.897-1}{2-1}$

          $\alpha =0.897$          

  The dissociation constant of KI is 0.87.