Question

Which of the following salts is insoluble in water at room temperature but soluble in boiling water?
A. \[{\rm{CaC}}{{\rm{l}}_{\rm{2}}}\]
B. \[{\rm{BaC}}{{\rm{l}}_{\rm{2}}}\]
C. \[{\rm{SrC}}{{\rm{l}}_{\rm{2}}}\]
D. \[{\rm{PbC}}{{\rm{l}}_{\rm{2}}}\]

Answer 1

Hint: Salts having chlorides as anions are generally ionic.
Regardless, all ionic solids are not necessarily soluble in water. Solubility relies on the solubility product of the ionic solid.
Insoluble salts settle and undergo precipitation.

Complete step by step solution:Solubility is the tendency of a chemical entity taken as solute to undergo dissolution in a solvent.
The solubility of a substance relies primarily on the physical and chemical characteristics of the solute and the solvent.
The degree of solubility of an entity in a provided solvent is estimated by the saturation concentration.
If we add solute to a solution, the solute doesn't enhance concentration, but rather undergoes precipitation at the end of the container.
Insolubility is the inability of the solute to undergo dissolution in the provided solvent.
Few ionic compounds undergo dissolution in water because of attraction between opposite charges.
Chlorides are generally soluble in water due to the appreciable value of solubility products.
We have to find out which chlorides are insoluble in water at room temperature but soluble in boiling water.
A. \[{\rm{CaC}}{{\rm{l}}_{\rm{2}}}\]
Group-2 elements like calcium form chlorides that are soluble in hot and cold water.
So, A is incorrect.
B. \[{\rm{BaC}}{{\rm{l}}_{\rm{2}}}\]
Group-2 elements like Ba form chlorides that are soluble in hot and cold water.
So, B is incorrect.
C. \[{\rm{SrC}}{{\rm{l}}_{\rm{2}}}\]
Group-2 elements like Sr form chlorides that are soluble in hot and cold water.
So, C is incorrect.
D. \[{\rm{PbC}}{{\rm{l}}_{\rm{2}}}\]
Ions like \[{\rm{P}}{{\rm{b}}^{{\rm{2 + }}}}\] form chlorides that are not soluble in water at room temperature but soluble in boiling water.
Lead chloride is insoluble in water at room temperature but soluble in boiling water.

So, option D is correct.
Note: Salts that are not soluble in water settle down through precipitation. The solubility of a substance relies primarily on the physical and chemical characteristics of the solute and solvent. The characteristics on which solubility relies are the temperature, pressure, and pH of the solution. Lead chloride, silver chloride, and mercurous chloride are insoluble in water at room temperature but soluble in boiling water.