Question

If the observed and theoretical mass of KCl is found to be 38.75 and 74.5, then the degree of dissociation of KCl is

• A. 92%
• B. 87%
• C. 68%
• D. 94%

Answer 1

The correct option is A 92%

$i=\frac{M_{th}}{M_{obs}}=\frac{74.5}{38.75}=1.92$

$\begin{array}{ccccc}KCl& \rightleftharpoons & K^{+}& +& C{l}^{-}\\ 1& & 0& & 0\\ 1-\alpha & & \alpha & & \alpha \end{array}$

$i=1-\alpha +\alpha +\alpha =1+\alpha$

$\alpha =i-1=1.92-1=0.92=92\%$