Question

${Cl}_2+2I^{-}\to I_2+2{Cl}^{-}$
The initial concentration of $I^{-}$ was $0.25mol$ $L^{-1}$ and the concentration after $10$ minutes $0.23mol$ $L^{-1}$. Calculate the rate of disappearance of $I^{-}$ and appearance of $I_2$.

Answer 1

$C{l}_2+2I^{-}⟶I_2+2{Cl}^{-}$

$-\frac{d\left[C{l}_2\right]}{dt}=-\frac{1}{2}\frac{d\left[I^{-}\right]}{dt}=\frac{d\left[I_2\right]}{dt}=\frac{1}{2}\frac{d\left[{Cl}^{-}\right]}{dt}$

Rate of decrease in moles$=\frac{0.23-0.25}{10minutes}$

Rate of disappearance of $I^{-}$ = $-0.002mol{L}^{-1}mi{n}^{-1}$

Rate of appearance of $I_2=-\frac{1}{2}\left(0.002\right)=0.001mol{L}^{-1}mi{n}^{-1}$