What is saturated solution How can one prepare a saturated solution of common salt in water class 6?

A saturated solution is a chemical solution containing the maximum concentration of a solute dissolved in the solvent. ​The additional solute will not dissolve in a saturated solution.

The amount of solute that can be dissolved in a solvent to form a saturated solution depends on a variety of factors. The most important factors are:

• Temperature: Solubility increases with temperature. For example, you can dissolve much more salt in hot water than in cold water.
• Pressure: Increasing pressure can force more solute into solution. This is commonly used to dissolve gases into liquids.
• Chemical Composition: The nature of the solute and solvent and the presence of other chemicals in a solution affects solubility. For example, you can dissolve much more sugar in water than salt in water. Ethanol and water are completely soluble in each other.

You encounter saturated solutions in daily life, not just in a chemistry lab. Also, the solvent does not need to be water. Here are some common examples:

• A soda is a saturated solution of carbon dioxide in water. This is why, when the pressure is released, carbon dioxide gas forms bubbles.
• Adding chocolate powder to milk so that it stops dissolving forms a saturated solution.
• Salt can be added to melted butter or oil to the point where the salt grains stop dissolving, forming a saturated solution.
• If you add enough sugar to your coffee or tea, you can form a saturated solution. You'll know you've reached the saturation point when the sugar stops dissolving. Hot tea or coffee allows much more sugar to be dissolved than you can add to a cold beverage.
• Sugar can be added to vinegar to form a saturated solution.

If one substance will not dissolve into another, you cannot form a saturated solution. For example, when you mix salt and pepper, neither dissolves in the other. All you get is a mixture. Mixing oil and water together will not form a saturated solution because one liquid does not dissolve in the other.

There's more than one way to make a saturated solution. You can prepare it from scratch, saturate an unsaturated solution, or force a supersaturated solution to lose some solute.

1. Add solute to a liquid until no more dissolves.
2. Evaporate solvent from a solution until it becomes saturated. Once the solution starts to crystallize or precipitate, the solution is saturated.
3. Add a seed crystal to a supersaturated solution so extra solute will grow onto the crystal, leaving a saturated solution.

The definition of a supersaturated solution is one which contains more dissolved solute than could ordinarily dissolve into the solvent. A minor disturbance of the solution or introduction of a "seed" or tiny crystal of solute will force crystallization of excess solute. One way supersaturation can occur is by carefully cooling a saturated solution. If there is no nucleation point for crystal formation, the excess solute may remain in solution.

Answer

Take a beaker and put 100 ml of water in it. Add one teaspoonful of salt to water and stir it with a glass rod until the salt dissolves completely. Again add a teaspoonful of salt and stir it well. We go on adding more and more salt in water with constant stirring to dissolve it. After adding a number of spoons of salt ,we will find that some salt is left undissolved at the bottom of the beaker. This means that no more salt can be dissolved in the quantity of water which we took in the beaker. The solution is now said to be saturated.

Saturated Solution

A solution in which no more substance can be dissolved at that temperature is called a saturated solution. A saturated solution contains the maximum amount of substance which can be dissolved in it at that temperature.

For ex: A maximum of 36 grams of salt can be dissolved in 100 grams of water at 20° C ,so a saturated solution of salt at 20° C contains 36 gram of salt dissolved in 100 grams of water.

Solubility

Solubility the maximum amount of a substance which can be dissolved in 100 grams of water at a given temperature is known as the solubility of that substance in water. Solubility of a substance refers to its saturated solution. Solubility of a substance depends on temperature .

The same quantity of water can dissolve different amount of different substances. The solubility of a substance in water increases on increasing the temperature. Larger amount of a substance can be dissolved in a given amount of water on heating it. The solubility of a substance decreases on lowering the temperature. Lesser amount of a substance will dissolve in a given amount of water on cooling it.

Effect of heating and cooling on saturated solution

If a saturated substance at a particular temperature is heated to a higher temperature, then the solubility  of substance increases and more of substance can be dissolved in it.

If the saturated solution of a substance at a particular temperature is cooled to a lower temperature, then the solubility of the substance decreases and some of the dissolved substance will separate out in form of solid crystals.

Hot water will dissolve more substance whereas cold water will dissolve less substance.