Which of the following is correct?

Options

A. The sum of mole fractions of all the components in a solution is always unity
B. Mole fraction depends upon temperature
C. Mole fraction is always negative
D. Mole fraction is independent of content of solute in solution

Answer

To solve the question, we need to analyze the statements provided regarding mole fractions in a solution. Let's break it down step by step.

### Step-by-Step Solution:

1. **Understanding Mole Fraction**:
- The mole fraction of a component in a solution is defined as the ratio of the number of moles of that component to the total number of moles of all components in the solution.
- For a solution with solute (A) and solvent (B), the mole fractions can be expressed as:
- Mole fraction of A (XA) = nA / (nA + nB)
- Mole fraction of B (XB) = nB / (nA + nB)

2. **Sum of Mole Fractions**:
- If we add the mole fractions of both components:
- XA + XB = (nA / (nA + nB)) + (nB / (nA + nB))
- This simplifies to (nA + nB) / (nA + nB) = 1
- Thus, the sum of the mole fractions of all components in a solution is always equal to unity (1).

3. **Analyzing the Statements**:
- **Statement 1**: "The sum of the mole fraction of all the components in the solution is always unity."
- This statement is **correct**.
- **Statement 2**: "Mole fraction depends upon temperature."
- This statement is **incorrect**. Mole fraction is a ratio and does not depend on temperature.
- **Statement 3**: "Mole fraction is always negative."
- This statement is **incorrect**. Mole fractions range from 0 to 1 and cannot be negative.
- **Statement 4**: "Mole fraction is independent of the content of solute in solution."
- This statement is **incorrect**. Mole fraction is directly dependent on the amount of solute and solvent present.

4. **Conclusion**:
- The only correct statement is the first one: "The sum of the mole fraction of all the components in the solution is always unity."

### Final Answer:
The correct option is **Statement 1**.