Henry's law states that the solubility of a gas (C) in a liquid is directly proportional to the partial pressure of the gas (P) above the liquid:
color(blue)(bar(ul(|color(white)(a/a) C = kPcolor(white)(a/a)|)))" "
where
k is a proportionality constant called Henry's law constant
If the two gases are in equal proportion,
P_"NH₃" = P_"CO₂" = "0.5 atm"
Then
C_"NH₃" = kP_"NH₃" = "61 mol·L"^"-1"color(red)(cancel(color(black)("atm" ^"-1"))) × 0.5 color(red)(cancel(color(black)("atm"))) = "30 mol/L"
C_"CO₂" = kP_"CO₂" = "0.034 mol·L"^"-1"color(red)(cancel(color(black)("atm" ^"-1"))) × 0.5 color(red)(cancel(color(black)("atm"))) = "0.017 mol/L"
C_"NH₃"/C_"CO₂" = (30 color(red)(cancel(color(black)("mol/L"))))/(0.017 color(red)(cancel(color(black)("mol/L")))) = 1800
