Question 1

Which of the following best describes what happens when sodium chloride (NaCl) dissolves in water?

Accepted Answer

NaCl dissociates into Na+ and Cl- ions, which become surrounded by water molecules forming hydration shells.

Question 2

What is the primary force that holds the ions together in a solid ionic crystal lattice such as table salt?

Accepted Answer

Electrostatic attraction between oppositely charged ions

Question 3

Why does solid NaCl not conduct electricity, but an aqueous solution of NaCl does?

Accepted Answer

Ions in solid NaCl are locked in place and cannot move, but in solution, ions are free to move and carry charge.

Question 4

Which part of a water molecule is attracted to a sodium ion (Na+) during the hydration process?

Accepted Answer

The oxygen atom, because it is partially negative (δ-)

Question 5

What is the term for the sphere of water molecules that surrounds an ion in solution?

Accepted Answer

Hydration shell

Question 6

Which equation correctly represents the dissociation of sodium chloride in water?

Accepted Answer

$$\mathrm{NaCl_{(s)} \rightarrow Na^+_{(aq)} + Cl^-_{(aq)}}$$

Question 7

Which property of water makes it an effective solvent for ionic compounds?

Accepted Answer

Its polarity, allowing it to interact with both cations and anions

Question 8

A patient receives an intravenous (IV) solution containing NaCl. Why is it important that the NaCl is dissolved in water before administration?

Accepted Answer

Dissolved NaCl allows the ions to be transported easily in the bloodstream, supporting nerve and muscle function.

Question 9

Which of the following best explains why the dissolution of NaCl in water is a physical change rather than a chemical change?

Accepted Answer

No new substances are formed; only the physical state of the ions changes.

Question 10

Which of the following steps occurs LAST during the solvation process of an ionic compound in water?

Accepted Answer

Hydration shells form around the separated ions.

Question 11

Which interaction is primarily responsible for the stabilization of ions in solution after dissociation?

Accepted Answer

Ion-dipole interactions between water molecules and ions

Question 12

If a salt solution conducts electricity, what does this indicate about the state of the ions?

Accepted Answer

The ions are free to move in the solution.

Question 13

Which of the following best describes the role of lattice energy in the dissolution of ionic compounds?

Accepted Answer

Lattice energy must be overcome by the attraction between ions and water molecules for dissolution to occur.

Question 14

A student adds NaCl to water and observes that the temperature of the solution decreases slightly. What does this suggest about the dissolution process?

Accepted Answer

The process is endothermic; energy is absorbed to break the ionic lattice.

Question 15

Which of the following is NOT a consequence of the solvation process in biological systems?

Accepted Answer

Creation of solid ionic lattices in cells

Question 16

Which equation represents the correct orientation of water molecules around a chloride ion (Cl-) in solution?

Accepted Answer

The hydrogen atoms (δ+) of water point toward Cl-

Question 17

Which of the following statements about electrolytes is TRUE?

Accepted Answer

Electrolytes are solutions that contain free-moving ions and can conduct electricity.

Question 18

Which of the following best explains why water is called a 'universal solvent'?

Accepted Answer

Water can dissolve both ionic and many polar covalent substances due to its polarity.

Question 19

A chemist wants to increase the rate at which NaCl dissolves in water. Which of the following would NOT help?

Accepted Answer

Adding more NaCl than can dissolve (creating a saturated solution)

Question 20

Which of the following is a real-world application of the solvation process?

Accepted Answer

The use of salt to melt ice on roads by dissolving in water and lowering the freezing point.

The Solvation Process: Dissociation and Hydration of Ionic Compounds

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