Question

Which of the following is not a typical property of an ionic compound?

• A. High melting point
• B. Conducts electricity in the molten and in an aqueous solution state.
• C. They are insoluble in water
• D. They exist as oppositely charged ions even in the solid state.

Answer 1

The correct option is C

They are insoluble in water

Part 1: The explanation of the correct option

Option C: They are insoluble in water

1. Water is composed of $\mathrm{H}\mathrm{and}\mathrm{O}$ atoms and has a significant electronegative difference, which creates a polarity between the bonded atom.
2. $\mathrm{O}$ being more electronegative than $\mathrm{H}$ pull bonded electron towards itself generating a partial negative charge on $\mathrm{O}$ and partial positive charge on $\mathrm{H}$.
3. Because of this polarity when an ionic compound is dissolved the charged ions of the ionic compound get attached with the atoms of ${\mathrm{H}}_2\mathrm{O}$ and breaks the bond making the compound soluble.
4. For example- $\mathrm{NaCl}$ is soluble in ${\mathrm{H}}_2\mathrm{O}$

Part 2: The explanation for incorrect options

Option A: High melting point

1. Because of the presence of strong intermolecular force in an ionic compound large amount of energy is needed to break the bond.
2. So Boiling and the melting point of an ionic compound are high.

Option B: Conducts electricity in the molten and in an aqueous solution state.

In the molten state of an aqueous solution, the ionic compound breaks into ions. which makes them good conductors of electricity.

Option D: They exist as oppositely charged ions even in the solid-state.

Ionic compound because of the presence of strong intermolecular force forms a lattice. which are held together by the oppositely charged ions.

So,Option C is correct. Insoluble in water is not a property of an ionic compound.