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NEET CHEMISTRYSome Basic Concepts of ChemistryEasy

Question

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

A

x<1x < 1

B

2x2- 2 \le x \le 2

C

0x10 \le x \le 1

D

xx is always non-negative

Step-by-Step Solution

  1. Definition: Mole fraction (xx) 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 (nn) is a count of particles, it must be non-negative (n0n \ge 0). Therefore, mole fraction xx is always non-negative (x0x \ge 0).
  3. Upper Limit: The sum of the mole fractions of all components in a mixture is unity (11) [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), xx must be strictly less than 1 (x<1x < 1) and greater than 0.
  5. Evaluate Option B: The range 2x2-2 \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.

Exam Context & Concepts Covered

This question aligns with the NEET CHEMISTRY syllabus, specifically targeting concepts from Some Basic Concepts of Chemistry. Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.

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