Question

Noble gases are named because of their inertness towards reactivity. Identify an incorrect statement about them

• A. Noble gases have large positive values of electron gain enthalpy
• B. Noble gases are sparingly soluble in water
• C. Noble gases have very high melting and boiling points
• D. Noble gases have weak dispersion forces

Answer 1

The Correct Option is C

Noble gases, known for their chemical inertness, exhibit distinct physical and chemical properties due to their full valence electron shells. Let's analyze each statement to identify the incorrect one:

1. Noble gases have large positive values of electron gain enthalpy: This is true. Noble gases have completed octet electron configurations which make them stable and non-tendency to accept additional electrons. Hence, their electron gain enthalpies are positive, indicating a non-favorable gain of electrons.
2. Noble gases are sparingly soluble in water: This statement is accurate. Due to their inertness and lack of reactivity, noble gases have very low solubility in water.
3. Noble gases have very high melting and boiling points: This is incorrect. Noble gases usually have low melting and boiling points due to their weak intermolecular forces (London dispersion forces). This is because they exist as monatomic gases with minimal interactions between atoms.
4. Noble gases have weak dispersion forces: This is true. The absence of stronger intermolecular forces like dipole-dipole interactions or hydrogen bonding leads to noble gases having weak dispersion forces, which ultimately results in their low melting and boiling points.

As analyzed, the statement "Noble gases have very high melting and boiling points" is incorrect because the low intermolecular forces in noble gases result in relatively low melting and boiling points. Thus, the correct answer is the third statement.