Final answer:
The more concentrated solution is due to the ionic compound NaCl because it dissociates into two types of ions, doubling the number of particles in solution compared to a molecular compound that does not dissociate.
Step-by-step explanation:
When comparing 1 mole of NaCl to 1 mole of a molecular compound, NaCl has a higher concentration in solution because it is an ionic compound that dissociates into its constituent ions. Every mole of NaCl that dissolves yields 1 mole of Na+ ions and 1 mole of Cl¯ ions, resulting in a total of 2 mol of particles in solution. Therefore, the more concentrated solution is due to NaCl because it provides more dissolved particles per mole as compared to a non-ionic molecular compound which would only provide 1 mole of particles per mole dissolved.
For example, dissolving 1 M NaCl results in a 1 M Na+ (aq) and 1 M Cl¯ (aq), thereby having a net particle concentration of 2 M. This ultimately means that the observed properties related to concentration, like colligative properties, will be twice as large for a 1 M solution of NaCl compared to a 1 M solution of a molecular compound like glucose (C6H12O6). This is because the molecular compound does not dissociate into additional particles.