Ions In Aquesous

Question 1

Polar nature of water

Answer 1

Oxygen has an electronegativity of 3,5 and hydrogen as an electronegativity of 2,1, this means that each shared pair is attracted stronger by the oxygen atom’s nucleus. Therefore the shared electron pairs are closer to the nucleus of oxygen than the hydrogen atom’s nucleus. Oxygen therefore obtains a slightly negative charge and each hydrogen atom a slightly positive charge. This causes a dipole forming, with oppositely charged sides and therefore is a polar molecule. (3,5 - 2,1 = 1,4. Therefore polar covalent)

Question 2

How water dissolves ions

Answer 2

The positive and negative ions are held together in a crystal by strong electrostatic forces (ionic bonds). The solid ionic crystal dissolves in a solution and forms ions. During the dissolution process the positive and negative ions have been broken loose from the crystal and spread through the solution. Energy is taken up in this process to break the bonds between new particles

Question 3

Hydration

Answer 3

The polar water molecules arrange themselves with their negative ends towards the positive ions and with their positive ends towards the negative ions. During this process energy is released.