Equal masses of H2, O2 and methane have been taken in a container of volume V at temperature 27°C in identical conditions. The ratio of the volumes of gases H2:O2:methane would be:

Assume that 100 g each of hydrogen, oxygen and methane are present.
The volume of gases is directly proportional to the number of moles of gases.
The molar mass of hydrogen, oxygen and methane are 2 g/mol, 32 g/mol and 16 g/mol respectively.
The number of moles of hydrogen, oxygen and methane are 100/2, 100/32 and 100/16 respectively.
The ratio of the volumes of hydrogen, oxygen and methane will be 100/2 : 100/32 : 100/16 = 1/1 : 1/16 : 1/8 = 16 : 1 : 2.
Option D is correct.