What dissolves in what?

The idea

Ionic compounds are generally soluble in water but insoluble in kerosene and petrol, whereas most covalent compounds are insoluble in water but dissolve in kerosene and petrol.

Salt and camphor

Sodium chloride is an ionic compound. Camphor is a covalent compound. Imagine adding each to water, and to kerosene.

Which one do you think dissolves in water?

• Sodium chloride
• Camphor
• Both dissolve in both liquids

Dissolve it?

Choose a compound and a liquid. This is a simulation, not an experiment to try at home.

Two patterns

Sodium chloride and copper sulfate dissolve in water but not in kerosene or petrol. Camphor and naphthalene do not dissolve in water but dissolve in kerosene and petrol.

Ionic compounds are generally soluble in water but insoluble in kerosene and petrol, whereas most covalent compounds are insoluble in water but dissolve in kerosene and petrol.

Notes

Ionic compounds: soluble in water, insoluble in kerosene and petrol. Most covalent compounds: insoluble in water, dissolve in kerosene and petrol.

Check yourself

Sodium chloride is an ionic compound. Where does it generally dissolve?

Camphor is a covalent compound. What happens when it is put in water?

In which liquid does naphthalene dissolve?

Which compound would stay undissolved in petrol?

• In kerosene. Ionic compounds are generally insoluble in kerosene.
• In petrol. Ionic compounds are generally insoluble in petrol.
• In water — correct. Yes!
• It does not dissolve — correct. Yes!
• It dissolves. Most covalent compounds, such as camphor, are insoluble in water.
• It forms ions in the water. Covalent compounds give no ions, and camphor is insoluble in water.
• Water. Naphthalene is insoluble in water.
• Kerosene — correct. Yes!
• None of the three liquids. Naphthalene dissolves in kerosene and petrol.
• Camphor. Camphor dissolves in kerosene and petrol.
• Naphthalene. Naphthalene dissolves in kerosene and petrol.
• Copper sulfate — correct. Yes!