Q13.53 P - Chemistry: Molecular Nature Of Matter And Change

Question

A solute has a solubility in water of  $\mathbf{21}\mathbf{g}\mathbf{/}\mathbf{kg}$ solvent. Is this value the same as $\mathbf{21}\mathbf{g}\mathbf{/}\mathbf{kg}$  solution? Explain.

Step-by-Step Solution

Answer

No, the value of  $\mathbf{21}\mathbf{g}\mathbf{/}\mathbf{kg}$ of solvent is different from the $\mathbf{21}\mathbf{g}\mathbf{/}\mathbf{kg}$ of solution.

 

Here, $\mathbf{21}\mathbf{g}\mathbf{/}\mathbf{kg}$ of solvent means, the total mass of the solution is 1021g whereas the  $\mathbf{21}\mathbf{g}\mathbf{/}\mathbf{kg}$ of solution means, the total mass of the solution is 1000g itself.

Step 1: Definition

The solution can be formed from the dissolution of the solute in the solvent. The solute decides the nature of the solution.

There are three types of the solution formed:

A saturated solution can be formed when there is solute to fill the spaces in the solvent and there is no more space to dissolve the solute.

An unsaturated solution is formed when there is enough space to dissolve the solute in the solvent.

A supersaturated solution is formed when there is more solute than the dissolved solute.

  

Step 2: Solubility Expression

The mass of the solution is the sum of the masses of both the solute and the solvent.

 $\text{Mass of solution = mass of solute + mass of solvent}$

 

$\mathbf{21}\mathbf{g}\mathbf{/}\mathbf{kg}$  of solvent means that there are 21 grams of mass of solutepresent in the 1kg or 1000 gran of the mass of solvent.The total mass of the solution is the sum of the mass of solute and mass of solvent which is equal to 1021 grams.

 

$\mathbf{21}\mathbf{g}\mathbf{/}\mathbf{kg}$ of the solution means that21g mass of solute is present in the 979g of solvent, therefore the total mass of the solution is 1000g.

 Therefore, both are different.