Question 1.46 - Chemistry: Molecular Nature Of Matter And Change

Question

Each of the beakers depicted below contains two liquids that do not dissolve in each other. Three of the liquids are designated A, B, and C, and water is designated W.                             

(a) Which of the liquids is (are) more dense than water and which less dense?

(b) If the densities of W, C, and A are 1.0 g/mL, 0.88 g/mL, and 1.4 g/mL, respectively, which of the following densities is possible for liquid B:

$\mathbf{0}\mathbf{.}\mathbf{79}\mathbf{ }\raisebox{1ex}{$\mathbf{g}$}\!\left/ \!\raisebox{-1ex}{$\mathbf{ml}$}\right.\mathbf{,}\mathbf{ }\mathbf{0}\mathbf{.}\mathbf{86}\mathbf{ }\raisebox{1ex}{$\mathbf{g}$}\!\left/ \!\raisebox{-1ex}{$\mathbf{ml}$}\right.\mathbf{,}\mathbf{ }\mathbf{0}\mathbf{.}\mathbf{94}\mathbf{ }\raisebox{1ex}{$\mathbf{g}$}\!\left/ \!\raisebox{-1ex}{$\mathbf{ml}$}\right.\mathbf{,}\mathbf{ }\mathbf{1}\mathbf{.}\mathbf{2}\mathbf{ }\raisebox{1ex}{$\mathbf{g}$}\!\left/ \!\raisebox{-1ex}{$\mathbf{ml}$}\right.$ ?

Step-by-Step Solution

Answer

Answer

 

1. Only solution A is denser than water.
2. 0.94 g/mL

Definition of density

Density is the typical property of the substance, formulated as mass divided by volume. The relation can be shown as:

 $\mathrm{Density} = \frac{\mathrm{Mass}}{\mathrm{Volume}}$

Identifying the trend of density on the basis of the diagram

There are three beakers manifested below.

Solutions in beakers

 

The solutions present in each of the beakers are insoluble with each other.

• Beaker A contains solution A and water.
• Beaker B contains solution B and water.
• Beaker C contains solution B and solution C.

 

The solution whose density is more will be present at the bottom, and the solution of less density will be present on the top layer.

 

In the case of beaker A, since solution A is present at the bottom and water is present on the top layer, water is less dense than solution A.

 

In the case of beaker B, since solution B is present at the top and water is present at the bottom layer, water is denser than solution B.

 

In the case of beaker C, since solution B is present at the bottom and solution C is present on the top layer, solution C is less dense than solution A.

 

On comparing the results, it can be concluded that only solution A is denser than water; the remaining solutions B and C are less dense than water.

Determining the value of solution B on the basis of density values of water, solution C and solution A.

On assuming the density of water, solution C and solution A as 1.0 g/mL, 0.88 g/mL, and 1.4 g/mL, respectively. The density of solution B can be determined as follows:

 

Since the density of solution B is less than that of water (1.0 g/mL) and more than that of solution C (0.88 g/mL). The approximate density will be .

 

The remaining value of density that are 0.79 g/mL, 0.86 g/mL and 1.2 g/mL are not possible. The reason can be explained separately as: 

• 0.79 g/mL is not possible since the solution is denser than solution C, and the value of density should be more than the density of solution C (0.88 g/mL).
• 0.86 g/mL is not possible since the solution is denser than solution C, and the value of density should be more than the density of solution C (0.88 g/mL).
• 1.2 g/mL is not possible since the solution is less dense than water, and the value of density should be less than the density of water (1.0 g/mL).