Answer:
the first option is the correct answer
The concentration of
in the stack gas = 12 ppmv
That means 12 L of
is present per 
The given temperature is 273 K (0 C) and pressure is 1 atm. At these conditions, 1 mol of gas would occupy,


V = 22.4 L
1 mol
occupies 22.4 L
Moles of
= 
Mass of
=
=
μg
Converting
:
= 
Calculating the concentration in μg/
:

B. Everyone else aren't trying to grow, they only complain.