`2% NaCl` as compared to `18%` glucose solution is

Options

A. Isoosmotic
B. Hypoosmotic
C. Hyperosmotic
D. None of the above

Answer

To determine the relationship between a 2% NaCl solution and an 18% glucose solution, we need to analyze their osmolarity, which is a measure of the concentration of solute particles in a solution.

### Step-by-Step Solution:

1. **Understanding Osmolarity**:
- Osmolarity is defined as the total concentration of solute particles in a solution. It is important to consider how many particles each solute dissociates into when dissolved in water.

2. **Calculating Osmolarity of 2% NaCl**:
- Sodium chloride (NaCl) dissociates into two ions: Na⁺ and Cl⁻.
- Therefore, a 2% NaCl solution will have an osmolarity of:
\[ \text{Osmolarity of NaCl} = 2\% \times 2 = 4 \text{ osmoles/L} \]

3. **Calculating Osmolarity of 18% Glucose**:
- Glucose (C₆H₁₂O₆) does not dissociate into ions; it remains as one particle.
- Thus, the osmolarity of an 18% glucose solution is simply:
\[ \text{Osmolarity of Glucose} = 18\% = 18 \text{ osmoles/L} \]

4. **Comparing Osmolarities**:
- Now we compare the osmolarities:
- 2% NaCl has an osmolarity of 4 osmoles/L.
- 18% glucose has an osmolarity of 18 osmoles/L.
- Since 4 osmoles/L (NaCl) is less than 18 osmoles/L (glucose), we conclude that the 2% NaCl solution has a lower concentration of solute particles.

5. **Determining the Type of Solution**:
- Since the 2% NaCl solution has a lower osmolarity compared to the 18% glucose solution, it is classified as **hypoosmotic**.
- Conversely, the 18% glucose solution is **hyperosmotic** compared to the 2% NaCl solution.

### Final Answer:
2% NaCl as compared to 18% glucose solution is **hypoosmotic**.