A student wishes to reduce the zinc ion concentration in a saturated zinc iodate solution to #1 xx 10^-6# M. How many moles of solid #KIO_3# must be added to 1.00 L of solution? [#K_(sp) Zn(IO_3)_2 = 4 xx 10^-6# at 25°C)?

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Answer 1 · 2018-06-01T18:17:23

So this is a #K_"sp"# problem, for which you have provided the relevant data...

We address the equilibrium...

#Zn(IO_3)_2(s) rightleftharpoonsZn^(2+)+2IO_3^(-)#...

for which #K_"sp"=[Zn^(2+)][IO_3^(-)]^2-=4.0xx10^-6#...

We will be requiring that #Zn^(2+)-=1.0xx10^-6*mol*L^-1# by the terms of the question...and thus we solve for #[IO_3^(-)]# in the given equation.....

#[IO_3^(-)]=sqrt(K_"sp"/[[Zn^(2+)]])=sqrt((4.0xx10^-6*mol*L^-1)/(1.0xx10^-6*mol*L^-1))#

#sqrt4=2*mol#...I must be clever cos I did this all in my nut!