Q4.10P - Chemistry: Molecular Nature Of Matter And Change

Question

Question: State whether each of the following substances is likely to be very soluble in water. Explain.

(a) Benzene, C₆H₆ (b) Sodium hydroxide (c) Ethanol, CH₂CH₂OH

(d) Potassium acetate.

Step-by-Step Solution

Answer

Answer

 

(a) Benzene,C₆H₆  is insoluble.

(b) Sodium hydroxide is soluble.

(c) Ethanol,CH₂CH₂OH  is soluble.

(d) Potassium acetate is soluble

Step 1: Determine the solubility of Ionic compounds in water

 The ionic compounds and the water molecules are polar in nature therefore both attract each other by the force of attraction.

Most ionic compounds dissociate and dissolve in water easily but if the force of attraction between ions of the ionic compound is stronger than the attraction force of water then its ionic bond does not dissociate and hence, these types of ionic compounds become water-insoluble.

 

Step 2: Predict the solubility of benzene in water

 

Benzene,${\mathit{C}}_{\mathbf{6}}{\mathit{H}}_{\mathbf{6}}$ is insoluble in water because it does not have a polar hydrogen bond in its structure, hence it is a non-polar compound while water is a polar compound.

 

Step 3: Determine the solubility of NaOH in water

 

Sodium hydroxide is soluble because it is an ionic compound that dissociates into ions on dissolving in water into $\mathbf{ }\mathit{N}{\mathit{a}}^{\mathbf{+}}$and $\mathit{O}{\mathit{H}}^{\mathbf{-}}$ions.

 

Step 4: Determine the solubility of ( CH 3 CH 2 OH ) in water

 

Ethanol,$\mathbf{\left(}{\mathbf{CH}}_{\mathbf{3}}{\mathbf{CH}}_{\mathbf{2}}\mathbf{OH}\mathbf{\right)}$ is soluble in water because it has a polar hydrogen bond in its structure.

Step 5: Determine the solubility of ( CH 3 COOK ) in water

 

Potassium acetate$\left(C{H}_{3}COOK\right)$ is soluble in water because it is an ionic compound, which will likely dissolve in water to form sodium ions and acetate ions that are held in solution through ion-dipole attractions to water.