Humber Admissions Practice Test

What occurs when ionic compounds dissolve?

1. They remain intact as whole molecules

2. They break apart atom by atom

3. They evaporate quickly

4. They form precipitates

The correct answer is: They break apart atom by atom

When ionic compounds dissolve, they dissociate into their individual ions. This process involves the breaking of the ionic bonds that hold the ions together in the solid state. In solution, these ions become surrounded by solvent molecules, typically water, allowing them to move freely. This characteristic behavior is fundamental to the properties of ionic compounds in solution, as it facilitates various chemical reactions and conductivity due to the mobility of the charged ions. The other choices do not accurately describe what occurs during the dissolution of ionic compounds. Whole molecules do not remain intact because ionic compounds are made up of ions, not distinct molecules like covalent compounds. Dissolving does not typically involve evaporation as a primary process, and precipitation is a result of reactions occurring in solution rather than a consequence of the dissolution of ionic compounds themselves.