Dissolving common salt in water is a chemical change or a physical change and give reasons?
Answer:
If you're at a lower level, physical only: since there's no chemical reaction taking place, it's just dissolution of a soluble solid in a liquid, which can easily be reversed by evaporating the liquid.
But at an advanced level, chemical reactions do occur: NaCl dissociates into Na+ and Cl- . The protons (H+) and hydroxyl ions (OH-) then recombine with Cl- and Na+ respectively to form the acid and the base. Now, since both species are strong in nature, the dissociation constant will be very close, but not EXACTLY the same, hence there will be an excess of either dissociated H+ or OH-. That will then change the pH of the solution accordingly.
It is a physical change because the ions disassociate but don't fundamentally change.
It's a physical change. The components of your salt (sodium ions + chloride ions) remain the same on dissolving; they don't rearrange atoms or electrons. It still tastes salty when you dissolve it. When you drive the water off by boiling it down, or just waiting for the water to evaporate, you recover the salt unchanged.
Dissolving common salt in water is a physical change as we can recover the same salt after evaporating the water. In fact when we put the salt in water it gets ionized and forms Na+ ion and Cl- ion,but these ions exist in solution only,that is why we can get back the common salt.
therefore,it is a physical change only.
the crystal lattice is broken (ionic bonds broken) and the ions are hydrated (hydrogen bonds formed). No *covalent* bonds are formed or broken, so it's not a chemical change. But the atoms really are in a different environment in solution, so the distinction is a bit arbitrary.
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