Under which condition can precipitation be avoided?
Answer and explanation
Correct answer: Keep ionic product less than solubility product
For a salt, precipitation is thermodynamically favoured when the current ionic product Q exceeds Ksp. Keeping Q below Ksp keeps the solution unsaturated, so the ions can remain dissolved without forming that solid phase. At Q equal to Ksp the solution is just saturated; raising Q above this value promotes precipitation. The remaining options either promote separation or are chemically meaningless.
Frequently asked questions
What is the correct answer to this question?
Keep ionic product less than solubility product
Why is this the correct answer?
For a salt, precipitation is thermodynamically favoured when the current ionic product Q exceeds Ksp. Keeping Q below Ksp keeps the solution unsaturated, so the ions can remain dissolved without forming that solid phase. At Q equal to Ksp the solution is just saturated; raising Q above this value promotes precipitation. The remaining options either promote separation or are chemically meaningless.
Which subject and chapter does this question cover?
This is a Class 11 Chemistry question. Chapter: Equilibrium. Topic: Solubility product and common ion effect.
