Equal quantities (50 ml) of the following four samples of water are placed in four beakers of 100 ml capacity . Their boiling points are determined accurately using the same thermometer . Which sample of water will having the lowermost boiling point as compared to other three samples ?

Options

A. Distilled water
B. Bottled mineral water
C. Well water
D. Seawater

Explanation

To determine which sample of water has the lowest boiling point among the four given samples (distilled water, mineral water, well water, and sea water), we can follow these steps:

### Step 1: Understand the Concept of Boiling Point
The boiling point of a liquid is the temperature at which it changes from a liquid to a gas. For pure water, this temperature is 100°C at standard atmospheric pressure.

### Step 2: Identify the Samples
The four samples of water are:
1. Distilled Water
2. Mineral Water
3. Well Water
4. Sea Water

### Step 3: Analyze the Composition of Each Sample
- **Distilled Water**: This is pure water with no dissolved salts or impurities. Its boiling point is 100°C.
- **Mineral Water**: This contains some dissolved minerals (salts), which will slightly increase its boiling point above 100°C.
- **Well Water**: This may contain various dissolved minerals and impurities, resulting in a boiling point higher than that of distilled water and mineral water.
- **Sea Water**: This has a high concentration of salts (around 3.5% salinity), which significantly raises its boiling point above 100°C.

### Step 4: Apply the Concept of Boiling Point Elevation
The boiling point elevation can be described by the formula:
\[ \Delta T_B = i \cdot K_B \cdot m \]
Where:
- \( \Delta T_B \) = change in boiling point
- \( i \) = van 't Hoff factor (number of particles the solute breaks into)
- \( K_B \) = ebullioscopic constant of the solvent
- \( m \) = molality of the solution

Since distilled water has no solutes, its boiling point remains at 100°C. The presence of salts in the other types of water increases their boiling points.

### Step 5: Compare the Boiling Points
- **Distilled Water**: 100°C (no salt)
- **Mineral Water**: Slightly above 100°C (some salt)
- **Well Water**: Higher than mineral water (more salt)
- **Sea Water**: Significantly higher than 100°C (high salt concentration)

### Conclusion
The sample of water with the lowest boiling point is **distilled water**, as it contains no dissolved salts. Therefore, the answer is:

**Distilled Water has the lowest boiling point among the four samples.**

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