Sodium chloride dissolves in water (solubility in water is 361g/1L), but copper (II) phosphate does not dissolve in water (insoluble).
A. Describe in a stepwise fashion how the solid sodium chloride dissolves in the water to form a solution. (name the resulting interparticle force of attraction).
B. Explain why sodium chloride is soluble in water and copper (II) phosphate is not.
A. The stepwise process of how sodium chloride dissolves in water can be described as follows:
1. Initially, we have solid sodium chloride, which consists of sodium ions (Na+) and chloride ions (Cl-) tightly held together by ionic bonds.
2. As the solid sodium chloride is added to water, the water molecules start to interact with the ionic lattice of the sodium chloride crystal.
3. The water molecules have a polar nature, where the oxygen atom is slightly negatively charged, and the hydrogen atoms are slightly positively charged. These partially charged regions of the water molecules attract the oppositely charged ions in the crystal lattice.
4. The positive end of the water molecule (the hydrogen atom) is attracted to the negatively charged chloride ion, while the negative end of the water molecule (the oxygen atom) is attracted to the positively charged sodium ion.
5. As the water molecules interact with the sodium chloride crystal, they surround individual ions, pulling them away from the lattice. This process is called hydration or solvation.
6. The water molecules form a solvation shell around each ion, effectively isolating it from the rest of the solid lattice.
7. As more and more ions are solvated, they become dispersed throughout the water, leading to the formation of a sodium chloride solution.
8. The resulting interparticle force of attraction in this case is the ion-dipole interaction, where the ions (solute) interact with the partial charges (dipole) of the water molecules.
B. Sodium chloride is soluble in water due to the strength of the ion-dipole interactions between the sodium and chloride ions and the water molecules. The polar nature of the water molecules allows them to effectively surround and solvate the sodium and chloride ions, preventing them from recombining into a solid lattice. This results in the formation of a homogeneous sodium chloride solution.
On the other hand, copper (II) phosphate is insoluble in water because the interparticle forces of attraction between the copper (II) phosphate compound and water molecules are not strong enough to overcome the forces holding the compound's ions together. The ionic lattice of copper (II) phosphate is more tightly bound compared to sodium chloride, making it difficult for water molecules to effectively solvate the ions and disperse them throughout the water. As a result, copper (II) phosphate remains in its solid form when added to water and does not dissolve.