Analyzing Boiling Points of Chloroform and Methane

The question asks us to verify the correctness of the stated boiling points for two common compounds: Chloroform and Methane. We need to check if the given values match the known boiling points for these substances under standard conditions.

Checking Statement I: Chloroform - 334K

Statement I claims that the boiling point of Chloroform is 334 Kelvin. Chloroform, with the chemical formula \(\text{CHCl}_3\), is a halomethane. Its boiling point is well-established. Let's look up the standard boiling point and compare it to the given value.

• The standard boiling point of Chloroform is approximately 61.2 degrees Celsius (\(61.2 \text{ °C}\)).
• To convert degrees Celsius to Kelvin, we use the formula: \(T(\text{K}) = T(\text{°C}) + 273.15\).
• Converting 61.2 °C to Kelvin: \(61.2 + 273.15 = 334.35 \text{ K}\).

The given boiling point of 334 K is very close to the calculated value of 334.35 K. In many contexts, this level of approximation is considered correct. Therefore, Statement I appears to be correct.

Checking Statement II: Methane - 111K

Statement II claims that the boiling point of Methane is 111 Kelvin. Methane, with the chemical formula \(\text{CH}_4\), is the simplest hydrocarbon (alkane). Its boiling point is also a known physical property. Let's verify this value.

• The standard boiling point of Methane is approximately -161.5 degrees Celsius (\(-161.5 \text{ °C}\)).
• Converting -161.5 °C to Kelvin: \(-161.5 + 273.15 = 111.65 \text{ K}\).

The given boiling point of 111 K is very close to the calculated value of 111.65 K. Similar to Chloroform, this value is considered correct within a typical range of precision. Therefore, Statement II also appears to be correct.

Conclusion on Correctness of Statements

Based on standard literature values for the boiling points of Chloroform and Methane, both statements provide values that are very close to the actual boiling points when expressed in Kelvin. The given values (334K for Chloroform and 111K for Methane) are generally accepted approximations.

Since both Statement I and Statement II are found to be correct, the pair of compound - boiling point is correct for both cases presented.

Identifying the Correct Option

We evaluated both statements:

• Statement I (Chloroform - 334K) is correct.
• Statement II (Methane - 111K) is correct.

The option that indicates both statements are correct is the right answer.

Revision Table: Boiling Point Facts

Additional Information: Factors Affecting Boiling Point

The boiling point of a substance is determined by the strength of the intermolecular forces holding the molecules together. Stronger intermolecular forces require more energy (higher temperature) to overcome, resulting in a higher boiling point.

• Intermolecular Forces: These include London dispersion forces, dipole-dipole interactions, and hydrogen bonding.
• Chloroform (\(\text{CHCl}_3\)): This molecule is polar due to the presence of chlorine atoms and its tetrahedral geometry (though slightly distorted). It exhibits dipole-dipole interactions in addition to London dispersion forces. This contributes to a relatively higher boiling point compared to nonpolar molecules of similar size.
• Methane (\(\text{CH}_4\)): This molecule is nonpolar due to its symmetrical tetrahedral structure. It only exhibits weak London dispersion forces between molecules. These forces are relatively weak, resulting in a very low boiling point.
• Molecular Size/Mass: For molecules with similar types of intermolecular forces, larger molecules generally have stronger London dispersion forces and thus higher boiling points. However, the type of intermolecular force is usually the dominant factor. Methane is a small molecule with weak forces, hence a very low boiling point. Chloroform is larger and polar, leading to a significantly higher boiling point.