Why is it necessary to filter the solution while its hot?

Answer 1

If you have a solution, you have a solute (usually a solid) dissolved in a solvent.

When you cool the solution, you increase the odds of the solute reassociating, thus forming solid crystals that you can then filter out to recover the product.

Answer 2

Filtering a solution while it is hot helps to remove any insoluble impurities or solid particles present in the solution. Hot solutions have higher solubility and are easier to filter, as the particles are more dispersed and can pass through the filter paper more easily. Cooling the solution may cause these impurities to precipitate out, making filtration more difficult.

Answer 3

I assume you are trying to recrystallize something. The substance you are trying to recrystallize is soluble when the solvent is hot but relatively insouble when the solution is cold. Ideally all impurities are either 1) soluble in both hot and cold solvent or 2) insoluble in hot or cold solvent. The soluble impurities will always remain in solution so you don't have to worry about it. The insoluble impurities can be filtered out. The reason the solution is kept hot during the filtration is to keep the target compound (the thing you are trying to recrystallize) in solution (remember, it is insoluble when the solution is cold so it will start to crystallize out of solution if it cools).

Answer 4

Im not sure what application you are using it for. But possibly to reduce soluability if the substance in the solvent is slightly soluable at a higher temp. Cooling it would force the substance out of solution so none wpuld be lost during filtration.

Answer 5

Because some of the compounds will solidify and precipitate when the solution is not hot. As a result the compound will be collected as the solid residue instead of the liquid filtrate.