Question

If you place 2 Osm of NaCl into water, what is the osmolarity of Na⁺ in water?

1) 0.5 Osm
2) 1.0 Osm
3) 1.5 Osm
4) 2.0 Osm

Answer 1

The osmolarity of Na+ in water when 2 Osm of NaCl is placed into it would be 2.0 Osm due to the dissociation of NaCl into Na+ and Cl- ions.

Step-by-step explanation:

If you place 2 osmoles (Osm) of NaCl into water, the osmolarity of Na+ in water would be 2.0 Osm. NaCl dissociates into two ions, Na+ and Cl-. Since the original question states 2 Osm of NaCl, and each mole of NaCl results in one mole of Na+ ions and one mole of Cl- ions, you would have 2 Osm of Na+ and 2 Osm of Cl- in solution, resulting in a combined osmolarity of 4.0 Osm but the osmolarity for each ion separately is 2.0 Osm.