Urinalysis and Body Fluids 6th Edition by Majorie DiLorenzo, Susan Strasinger

Exercise 49

Clinical osmometers use NaCl as a reference solution because:

A. 1 g molecular weight of NaCl will lower the freezing point 1.86oC

B. NaCl is readily frozen

C. NaCl is partially ionized similar to the composition of urine

D. 1 g equivalent weight of NaCl will raise the freezing point 1.86oC

Step 1 of 2

Clinical osmometers:

The osmometer is used to detect osmotic pressure of a solution.

• The osmometers use NaCl (Sodium Chloride) solution as a reference solution in it because NaCl have half-done ionized substances.

• This half-done ionized substance resembles the composition of urine which is also having half-done ionized substances in it, which makes it easy to use NaCl.

Therefore, NaCl is used in clinical osmometers as reference solution because of “half-done ionized substance present in NaCl is similar to urine composition”. Hence, the correct answer is option.