A student conducts an experiment to determine the molar mass of an unknown pure volatile liquid using the vapor density method. A sample of the liquid is completely vaporized in a closed container, and the temperature, pressure, volume, and mass of the vapor are recorded across three separate trials at \(300\text{ K}\).

Trial	Pressure (\(\text{atm}\))	Volume (\(\text{L}\))	Temperature (\(\text{K}\))	Mass of vapor (\(\text{g}\))
1	\(1.00\)	\(0.246\)	\(300\)	\(0.88\)
2	\(0.50\)	\(0.492\)	\(300\)	\(0.88\)
3	\(0.75\)	\(0.246\)	\(300\)	\(0.66\)

The student consults the following reference table of candidate volatile liquids:

Candidate liquid	Molecular formula	Molar mass (\(\text{g/mol}\))
Ethanol	\(\text{C}_2\text{H}_6\text{O}\)	\(46\)
Acetone	\(\text{C}_3\text{H}_6\text{O}\)	\(58\)
Diethyl ether	\(\text{C}_4\text{H}_{10}\text{O}\)	\(74\)
Ethyl acetate	\(\text{C}_4\text{H}_8\text{O}_2\)	\(88\)

Based on the experimental data, which of the candidate liquids is the unknown, and which statement provides the correct justification?