Some of the following are true solution :-
`{:(I,:,"urea solution",,II,:,Gelation),(III,:,"Glucose solution",,IV,:,"NaCl solution"),(V,:,But ter,,VI,:,"Blood"):}`
Select true solution

Options

A. I,III,IV
B. II,III,IV,V
C. I,IV,V
D. II,IV,VI

Answer

To determine which of the given options are true solutions, we need to understand the definition of a true solution. A true solution is a homogeneous mixture where the size of the solute particles is less than 1 nanometer (10^-9 meters). In a true solution, the solute completely dissolves in the solvent, and the resulting mixture is transparent.

Let's analyze each option step by step:

1. **Urea Solution**:
- Urea is a crystalline solid that dissolves completely in water.
- The size of urea particles is less than 1 nanometer when dissolved.
- Therefore, **Urea solution is a true solution**.

2. **Gelatin**:
- Gelatin is a colloid, which means it has larger particles (between 1 nanometer and 10,000 nanometers).
- It does not form a true solution because the particles are not completely dissolved.
- Therefore, **Gelatin is not a true solution**.

3. **Glucose Solution**:
- Glucose is a crystalline solid that dissolves completely in water.
- The size of glucose particles is also less than 1 nanometer when dissolved.
- Therefore, **Glucose solution is a true solution**.

4. **NaCl Solution**:
- Sodium chloride (table salt) dissolves completely in water.
- The size of NaCl particles is less than 1 nanometer when dissolved.
- Therefore, **NaCl solution is a true solution**.

5. **Butter**:
- Butter is a colloid and does not dissolve completely in water.
- It consists of larger particles and is classified as an emulsion.
- Therefore, **Butter is not a true solution**.

6. **Blood**:
- Blood is also a colloid, containing cells and proteins suspended in plasma.
- It does not form a true solution due to the presence of larger particles.
- Therefore, **Blood is not a true solution**.

### Conclusion:
The true solutions from the given options are:
- Urea solution (I)
- Glucose solution (III)
- NaCl solution (IV)

### Final Answer:
The true solutions are **I, III, and IV**.

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