Question

Isotonic solutions must have the same:
A.Solute
B.Density
C.Elevation in boiling point
D.Depression in freezing point

Answer 1

An isotonic solution is one that has the same osmolarity, or solute concentration, as another solution. If these two solutions are separated by a semipermeable membrane, water will flow in equal parts out of each solution and into the other.

Complete step by step answer:
Two solutions having the same osmotic pressure across a semipermeable membrane are referred to as isotonic solutions. It has the same osmolarity (solute concentration), as another solution. A solution is isotonic when its effective osmole concentration is the same as that of another solution. This state provides the free movement of water across the membrane without changing the concentration of solutes on either side. Some examples of isotonic solutions are 0.9% normal saline and lactated ringers.
Isotonic solutions have the same osmotic pressure and same concentration. Elevation in boiling point and depression in freezing point are both colligative properties. These two colligative properties depend upon concentration.
As the molar concentration is the same for isotonic solutions, so elevation in boiling point and depression in freezing point of isotonic solutions must be the same.

Hence the correct option will be C,D.

Note: Elevation in boiling point: Boiling point elevation refers to the increase in the boiling point of a solvent upon the addition of a solute. When a non-volatile solute is added to a solvent, the resulting solution has a higher boiling point than that of the pure solvent. For example, the boiling point of a solution of sodium chloride (salt) and water is greater than that of pure water.
Depression in freezing point: Freezing point depression refers to the lowering of the freezing point of solvents upon the addition of solutes. It is a colligative property of solutions that is generally proportional to the molality of the added solute.