Which of the following options incorrectly describes the possible range of values for the mole fraction ($x$)

Question

Which of the following options incorrectly describes the possible range of values for the mole fraction ($x$) of a component in a mixture?

Accepted Answer

1. **Definition:** Mole fraction ($x$) is the ratio of the number of moles of a specific component to the total number of moles of all components in the solution [Class 12 Chemistry, Ch 1, Sec 1.2.1, Eq 1.4].
2. **Non-negativity:** Since the number of moles ($n$) is a count of particles, it must be non-negative ($n \ge 0$). Therefore, mole fraction $x$ is always non-negative ($x \ge 0$).
3. **Upper Limit:** The sum of the mole fractions of all components in a mixture is unity ($1$) [Class 12 Chemistry, Ch 1, Sec 1.2.1, Eq 1.7]. Consequently, the mole fraction of any single component cannot exceed 1.
4. **Mixture Constraint:** For a mixture (implying at least two components present), $x$ must be strictly less than 1 ($x < 1$) and greater than 0.
5. **Evaluate Option B:** The range $-2 \le x \le 2$ implies that mole fraction can be negative or greater than 1, both of which are physically impossible. Thus, this description is incorrect.

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