Answer:
Methane (B) is expected to have the lowest boiling point.
Step-by-step explanation:
There are to ways of solving this problem.
The first one is considering the physical state of matter that this compounds are found in normal conditions (room temperature):
(A) calcium carbonate - solid
(B) methane - gas
(C) methanol (CH₄O) - liquid
(D) dimethyl ether (CH₃OCH₃) - liquid
Methane is the only gas, therefore it has the lowest boiling point.
The second one is considering the molecular interactions between the molecules of each compound:
(A) calcium carbonate - it is a salt - eletrostatic interactions between ions - very strong
(B) methane - non-polar molecule - induced dipole - very weak
(C) methanol (CH₄O) - polar molecule - dipole-dipole - relatively strong
(D) dimethyl ether (CH₃OCH₃) - liquid - dipole-dipole - relatively strong
The intermolecular interactions in methane are the weakest, therefore it has the lowest boiling point.