At NTP, density of a gas is 0.0045g/ml. The vapour density and molecular weight will be

At NTP, density of a gas is 0.0045g/ml. The vapour density and molecular weight will be NTP

Dear student
Density of the  gas = 0.00045g/mL
1L contains   0.00045g of gas
Then 22.4 L of the gas will contain  = 0.00045 x 22.4/10^-3 = 10.08g 
Molecular mass of the gas is thus 10.08
Vapour density = molecular mass / 2 = 10.08 / 2 =  5.04
So the correct option is (D)

Regards.