Physical Properties of Ionic Substances

Question 1

what are the physical properties of ionic substances?

Answer 1

• high melting and boiling points
• can conduct electricity in molten or aqueous state but not in solid state
• usually soluble in water but not in organic solvents

Question 2

explain why ionic substances have high melting and boiling points

Answer 2

• oppositely charged ions are held together by strong electrostatic forces of attraction
• a lot of energy is needed to overcome these forces
• hence have high melting and boiling points

Question 3

explain why ionic substances can conduct electricity in molten or aqueous state but not in solid state

Answer 3

• solid state -> ions are held together in a fixed ionic lattice structure
• not free to move so cannot act as charge carriers to conduct electricity
• molten/aqueous state -> ions are free to move so can conduct electricity

Question 4

explain why ionic substances are usually soluble in water but not in organic solvents

Answer 4

water molecules can separate the positive ions from the negative ions, causing them to dissolve