Question

If the ion product of barium sulfate is 1.0 x 10-9 a precipitate will form

True or False? Why?

The ion product of a salt dissolved in water is less than its Ksp value. In this case a precipitate:

a. will not form

b. will form 

Why?

Answer 1

For doing this problem the value of K_SP for Barium sulphate should be known.

K_SP for Barium sulphate =1.1*10^-10

The decision rule is that in order for a reaction to form precipitate, the value of ionic product should be more than K_SP value.

In the given reaction the ionic product is more than K_SP value.                                     ( 1.0 x 10-9 >1.1*10^-10)

Thus, the statement is true.

Answer to second part,

As the ionic product is less than that of K_SP value the mixture is completely dissolved in water or no precipitate is formed.

Solubility product (K_SP value. ) is determined for saturated solutions and constant at a particular temperature.

Until the ionic product becomes equal to K_SP value precipitation is not formed.

When the ionic product becomes more than K_SP value from there onwards the precipitation starts.

Thus the answer: a) precipitate Will not be formed