Question

Which of the following salt has the same value of vant?s Hoff factor as that of $K _{3}\left[ Fe ( CN )_{6}\right]$ ?

• A. $Na _{2} SO _{4}$
• B. $Al \left( NO _{3}\right)_{3}$
• C. $Al _{2}\left( SO _{4}\right)_{3}$
• D. $Fe _{3} O _{4}$

Answer 1

Answer: (B)

$Al \left( NO _{3}\right)_{3}$

Answer 2

$K _{3}\left[( FeCN )_{6}\right]$ on ionisation gives 4 species $\left(3 K ^{+}\right.$ and $\left.1\left[ Fe ( CN )_{6}\right]^{3-}\right)$ and $Al \left( NO _{3}\right)_{3}$ also gives 4 species $\left(1 Al ^{3+}\right.$ and $\left.3 NO _{3}^{-}\right)$, thus both will have same value of Van't Hoff factor.