Your professor is an exceptional chemist if he can extract hydrogen ions by the electrolysis of water and ozonize "CO"_2 in the Martian atmosphere to "CO" and create an explosion at 1.25 atm pressure.
We should send him on the next rocket to Mars.
I presume that you are expected to use the reaction
"NO"_3^"-" + "CO" → "N"_2 + "CO"_2
The half-reactions are:
"2NO"_3^"-" + "12H"^"+" + "10e"^"-" → "N"_2 + "6H"_2"O"
5×["CO" + "H"_2"O" → "CO"_2 + "2H"^"+" + "2e"^"-"]
"2NO"_3^"-" + "5CO" + "2H"^"+" → "N"_2 + "5CO"_2 + "H"_2"O"
We see that 2 mol of "NO"_3^"-" gives 6 mol of gas (1 mol of "N"_2 and 5 mol of "CO"_2). The water will be a liquid under these conditions.
"Moles of gas" = 200.0 color(red)(cancel(color(black)("g NO"_3^"-"))) × (1 color(red)(cancel(color(black)("mol NO"_3^"-"))))/(62.00 color(red)(cancel(color(black)("g NO"_3^"-")))) × "6 mol gas"/(2 color(red)(cancel(color(black)("mol NO"_3^"-")))) = "9.677 mol gas"
PV = nRT
V = (nRT)/P
T = "17 °C" = "290.15 K"
"P = 1.25 atm"
V = (nRT)/P = (9.677 color(red)(cancel(color(black)("mol"))) × "0.082 06" "L"·color(red)(cancel(color(black)("atm·K"^"-1""mol"^"-1"))) ×290.15 color(red)(cancel(color(black)("K"))))/(1.25 color(red)(cancel(color(black)("atm")))) = "184 L"
chi_"N₂" = 1/6, and chi_"CO₂" = 5/6.
P_"N₂" = chi_"N₂"P_"tot" = 1/6 × "1.25 atm" = "0.208 atm"
P_"CO₂" = chi_"CO₂"P_"tot" = 5/6 × "1.25 atm" = "1.04 atm"
