Question

For the reaction,
$F{e}^{2+}+3dipyridyl\iff \left[Fe\right(dipyridyl{)}_3{]}^{2+}{r}_f=1.45\times {10}^{13}\left[F{e}^{2+}\right][dipyridyl{]}^3{r}_b=1.22\times {10}^{-4}[Fe\left(dipyridyl\right){]}^{2+}$
The stability constant for the complex is

• A. $1.19\times {10}^4$
• B. $1.19\times {10}^{17}$
• C. $1.19\times {10}^6$
• D. $1.19\times {10}^8$

Answer 1

The correct option is B $1.19\times {10}^{17}$

$K_5=\frac{\left[Fe\right(dipyridyl{)}_3{]}^{2+}}{\left[F{e}^{2+}\right[dipyridyl{]}^3}=\frac{1.45\times {10}^{13}}{1.22\times {10}^{-4}}=1.19\times {10}^{17}\because r_f=r_b$ at equilibrium