Which one of the following is the correct sequence in increasing order of molecular weights of the hydrocarbons? A. Methane, Ethane, Propane and Butane B. Propane, Butane, Ethane and Methane C. Butane, Ethane, Propane and Methane D. Butane, Propane, Ethane and Methane

The correct answer is A. Methane, Ethane, Propane and Butane.

The molecular weight of a molecule is the sum of the atomic weights of the atoms in the molecule. The atomic weight of carbon is 12, the atomic weight of hydrogen is 1, and the molecular weights of methane, ethane, propane, and butane are 16, 30, 44, and 58, respectively. Therefore, the correct sequence in increasing order of molecular weights of the hydrocarbons is A. Methane, Ethane, Propane and Butane.

Option B is incorrect because the molecular weight of propane is greater than the molecular weight of ethane.

Option C is incorrect because the molecular weight of butane is greater than the molecular weight of propane.

Option D is incorrect because the molecular weight of butane is greater than the molecular weight of methane.