A 1.2% Solution of NaCl is Isotonic
A 1.2% solution of NaCl (sodium chloride) is considered isotonic. This means that it has the same osmotic pressure as the intracellular fluid of human red blood cells. Let's break down why this is important:
What is Osmosis?
Osmosis is the movement of water molecules across a semipermeable membrane from an area of high water concentration to an area of low water concentration. This movement continues until the concentration of water is equal on both sides of the membrane.
What is Isotonic?
Isotonic solutions have the same concentration of solutes as the intracellular fluid of cells. This means that water will move in and out of the cell at equal rates, maintaining the cell's volume and function.
What Happens When Solutions are Not Isotonic?
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Hypotonic solutions: These solutions have a lower concentration of solutes than the intracellular fluid. Water will move into the cell, causing it to swell and potentially burst (lyse).
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Hypertonic solutions: These solutions have a higher concentration of solutes than the intracellular fluid. Water will move out of the cell, causing it to shrink (crenate).
Why is a 1.2% NaCl Solution Isotonic?
A 1.2% NaCl solution has a similar osmotic pressure to human blood plasma. This is because the concentration of solutes in the solution is roughly the same as the concentration of solutes in the blood. As a result, water will move in and out of red blood cells at equal rates, maintaining their volume and preventing them from bursting or shrinking.
Practical Applications
Isotonic solutions like a 1.2% NaCl solution are used in various medical applications, including:
- Intravenous (IV) fluid administration: Isotonic solutions are used to replenish fluids and electrolytes in patients who are dehydrated.
- Eye drops: Isotonic eye drops help to maintain the health of the eye by preventing the cornea from swelling or shrinking.
- Contact lens solutions: Isotonic solutions are used to clean and store contact lenses, preventing damage to the cornea.
Conclusion
A 1.2% solution of NaCl is considered isotonic because it has the same osmotic pressure as the intracellular fluid of human red blood cells. This makes it ideal for medical applications where it is crucial to maintain the volume and function of cells.
