Water Dissociation: H+ & OH- Ions Upon Ionic Compound Addition

In summary, when an ionic compound is added to pure water, it will dissociate into ions such as H+ and OH-, due to the high dipole moment and dielectric constant of water. This allows the ions to be solvated and neutralizes their charges, making separation easier. In the electrolysis of water, H+ ions will go to the cathode and become H2 gas, while the OH- ions will become O2. This is due to the dissociation of water molecules into H+ and OH- ions.
  • #1
Kyoma
97
0
Pure water is made up of water molecules, no free moving ions. However, if you add an ionic compound, say copper sulfate into water, Cu2+ and SO42- will be produced, so will H+ and OH- ions.

Why will water molecules dissociate into hydrogen and hydroxide ions when an ionic compound is added? Why will the ionic compounds dissociate in water?
 
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  • #2
Kyoma said:
Pure water is made up of water molecules, no free moving ions. However, if you add an ionic compound, say copper sulfate into water, Cu2+ and SO42- will be produced, so will H+ and OH- ions.

That's incorrect, see water autodissociation.
 
  • #3
o_O

Then why will some ionic compounds (or covalent compounds) dissociate only in the presence of water? What makes water so special?
 
  • #4
High dipole moment and high dielectric constant, ions are solvated which to some extent neutralizes their charges and makes separation easier.
 
  • #5
Hi,

As we know that in the electrolysis of water we get oxygen and hydrogen, but how, water dissosites as H+ and HO- , so H+ would go to the cathode and become H2(gas) but what would become of the OH- ion? how it will become O2?.
 

What is water dissociation?

Water dissociation is the process in which a water molecule (H2O) breaks apart into two ions: a positively charged hydrogen ion (H+) and a negatively charged hydroxide ion (OH-).

What causes water dissociation to occur?

Water dissociation occurs due to the polar nature of water molecules. The unequal distribution of electrons in a water molecule leads to the formation of H+ and OH- ions.

How does the addition of an ionic compound affect water dissociation?

The addition of an ionic compound to water can increase or decrease the concentration of H+ and OH- ions, depending on the nature of the compound. Ionic compounds can also act as electrolytes, facilitating the dissociation of water molecules.

What is the significance of H+ and OH- ions in water dissociation?

H+ and OH- ions play important roles in various chemical and biological processes. They can act as acids or bases, participate in neutralization reactions, and regulate the pH of a solution.

How does water dissociation relate to the concept of pH?

pH is a measure of the concentration of H+ ions in a solution. Water dissociation plays a crucial role in determining the pH of a solution, as the concentration of H+ ions is directly proportional to the acidity of a solution.

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