Question

What is the solubility of Ca(IO3)2 6H2O in

(a) water;

in (b) 0.150 M NaIO3;

and in (c) 0.085 M Ca(NO3)2? For Ca(IO3)2 6H2O, Ksp = 2.03 x 10-6

Answer 1

Ca(IO₃)2 =>Ca²⁺+2IO₃^-

Given that Ksp is 2.03*10-6.From the equation we see that when x moles of the salt dissolves we get x moles of Ca2+ and 2x moles of iodate ions .Hence

Ksp=>[Ca²⁺][IO₃^-]²

=>(x)(2x)²

=>4x³ =2.03*10-6

Value of x=7.976*10-3.

x = 0.007976g moles of the Ca(IO3)2 6H2O dissolves per litre of solution ,Hence solubility in water is 7.976*10-3 moles/l

b)NaIO₃=>Na⁺+IO3^-

Here solubility of the salt in NaIO₃ is asked.So we have to take the common ion effect into consideration.Even NaIO₃ has an iodate ion,we have to consider 0.150 moles of iodate ions into consideration.So the equation of ksp modifies as

Ksp=>[Ca²⁺][IO₃^-]²

=>(x)(2x+0.150)²=2.03*10-6

The value of x can be solved as 8.867*10-5 moles/litre.

Hence solubility of Ca(IO3)2 6H2O in 0.150 M NaIO3 is 8.867*10-5 moles/litre.

c)Ca(NO₃)₂=>Ca2+ +2NO₃^-.

Here also have to take the common ion effect into consideration.Even Ca(NO₃)₂ has a calcium ion,we have to consider 0.085 moles of calcium ions into consideration.So the equation of ksp modifies as

Ksp=>[Ca²⁺][IO₃^-]²

=>(x+0.085)(2x)²=2.03*10-6

The value of x can be solved as 2.3919-10-3 moles/litre.

Hence solubility of Ca(IO3)2 6H2O in 0.085 M Ca(NO3)2 is 2.3919-10-3 moles/litre.