Question

When an ionic compound such as sodium chloride (NaCl) is placed in water, the component atoms of the NaCl crystal dissociate into individual sodium ions (Na+) and chloride ions (Cl-). In contrast, the atoms of covalently bonded molecules (e.g., glucose, sucrose, glycerol) do not generally dissociate when placed in aqueous solution. Which of the following solutions would be expected to contain the greatest number of solute particles (molecules or ions)?
A) 1 L of 0.5 M NaClB) 1 L of 0.5 M glucoseC) 1 L of 1.0 M NaClD) 1 L of 1.0 M glucoseE) C and D will contain equal numbers of particles.

Answer 1

Answer:

The correct answer is C) 1 L of 1.0 M NaCl

Explanation:

NaCl is a ionic compound so it dissociates in water into Na⁺ and Cl⁻ ions. Glucose is a covalent solute so it does not dissociates into ions. So, when we dissolve NaCl we have twice the amount of particles in solution in comparison with glucose. According to this:

A) and B) are solutions with the same concentration (0.5 M) but NaCl solution will have more solute particles than glucose.

C) and D) are solutions with more solute amount because they are more concentrated (1 M), but NaCl solution will have more solute particles than glucose solution ( 1 mol of Na⁺ ions + 1 mol of Cl⁻ ions).

The solution with the greatest solute particle number is C).