Which compound has the highest molar mass

Option (a) is the correct answer.

Explanation:

Molar mass of a substance means the sum of atomic masses of all the atoms present in a substance.

A polyethylene molecule is made up of "n" number of repeated units ethylene. Hence, it will have highest molar mass because there are more number of atoms present in a polyethylene molecule.

Whereas an ethane molecule is and its molar mass is = 30 g/mol

An octane molecule is and its molar mass is = 114 g/mol

An octanal molecule is and its molar mass is = 128 g/mol

Thus, we can conclude that polyethylene, a polymer of ethane has the highest molar mass.