1. Dissolving Table Salt
* Ionic Bonds: Table salt is composed of sodium (Na+) and chloride (Cl-) ions held together by strong ionic bonds.
* Polar Water Molecules: Water (H2O) is a polar molecule, meaning it has a slightly positive end (near the hydrogen atoms) and a slightly negative end (near the oxygen atom).
* Attraction and Dissociation: When salt is added to water, the polar water molecules surround the Na+ and Cl- ions. The positive end of water molecules attracts the negative chloride ions (Cl-), while the negative end of water molecules attracts the positive sodium ions (Na+). This attraction overcomes the ionic bond holding the ions together, causing the salt to dissolve.
2. Formation of Ions in Solution
* Dissociation: As the salt dissolves, the Na+ and Cl- ions become surrounded by water molecules and separate (dissociate) from each other. This creates a solution containing free, mobile ions.
3. Conductivity
* Charge Carriers: The dissolved ions (Na+ and Cl-) are now free to move throughout the solution. These ions act as charge carriers.
* Electric Current: When an electric potential (voltage) is applied across the solution, the positively charged Na+ ions move towards the negative electrode (cathode), and the negatively charged Cl- ions move towards the positive electrode (anode). This movement of charged particles constitutes an electric current.
In Summary:
* Table salt dissolves in water due to the attraction between water molecules and the ions in the salt.
* The dissolved salt creates a solution containing free, mobile ions.
* These ions act as charge carriers, allowing the solution to conduct electricity.
Important Note: Pure water itself is a very poor conductor of electricity because it contains very few free ions. Adding dissolved salts (like table salt) significantly increases the conductivity.
