Question

how to calculate the molar solubility from Ksp values???

Answer 1

To calculate the molar solubility of a salt from its value, we follow the following steps-

• First of all, we have to write down the balanced solubility equilibrium of the salt. Let us take an example to understand the step.

Consider the salt (we want to use the complex example so that the rest becomes easy!). Now, we have to establish its solubility equilibrium as below-

• The next step will be to assume to molar solubility of the salt to be (M).
• Now, from the solubility equilibrium given above, we will evaluate the individual solubilities of the ions. The solubility of is and the solubility of is . This is done according to the stoichiometry of the balanced solubility equilibrium. The purpose of this step is to set up the solubility constant equation and calculate from the known value which is the next step.
• We set up the solubility constant equation and calculate as below-

So, as we discussed above, the molar solubility of any salt can be calculated following the above steps. We just need a known value of the for that.