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Question and Answer

The van't Hoff factor of \(0.1\:M\:La(NO_3)_3\) solution is found to be \(2.74,\) the percentage dissociation of the salt is:
(A) \(\;85\%\)
(B) \(\;58\%\)
(C) \(\;65.8\%\)
(D) \(\;56.8\%\)

Answer

Answer: B
Formula for the relation between van't Hoff factor and percentage of dissociation is as follows.
\(van't\ Hoff's\ factor(i)=1+\dfrac { \alpha }{ 100% } (n-1)\)

\( \quad \quad \quad \quad \quad \quad \quad \quad 2.74=\ 1+\dfrac { \alpha }{ 100% } (4-1)\\ \quad \quad\quad \quad \quad \quad \quad \quad \quad \alpha =58%\\ \)

So percentage of dissociation \(= 58\)%.

So the answer is option B.
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