A fluid gas produced on burning furnace oil contains 0.15 gm mole of CO₂, 0.05 gm mole of oxygen and 0.80 gm mole of N₂. What is its molecular weight ?

ANS:C - 30.6

To find the molecular weight of the gas mixture, we need to calculate the total mass of all the gas molecules and then divide by the total number of moles. Given:

• Molar mass of CO2=44 g/molMolar mass of CO2​=44g/mol
• Molar mass of O2=32 g/molMolar mass of O2​=32g/mol
• Molar mass of N2=28 g/molMolar mass of N2​=28g/mol

First, let's calculate the total mass of each gas:

• Mass of CO2 = 0.15 gm mole×44 g/mol=6.6 g0.15gm mole×44g/mol=6.6g
• Mass of O2 = 0.05 gm mole×32 g/mol=1.6 g0.05gm mole×32g/mol=1.6g
• Mass of N2 = 0.80 gm mole×28 g/mol=22.4 g0.80gm mole×28g/mol=22.4g

Now, let's calculate the total mass of the gas mixture:

• Total mass = Mass of CO2 + Mass of O2 + Mass of N2 = 6.6 g+1.6 g+22.4 g=30.6 g6.6g+1.6g+22.4g=30.6g

Now, let's calculate the total number of moles of the gas mixture:

• Total moles = Moles of CO2 + Moles of O2 + Moles of N2 = 0.15 gm mole+0.05 gm mole+0.80 gm mole=1 gm mole0.15gm mole+0.05gm mole+0.80gm mole=1gm mole

Finally, let's calculate the molecular weight:

• Molecular weight = Total mass / Total moles = 30.6 g/1 gm mole=30.6 g/mol30.6g/1gm mole=30.6g/mol

So, the molecular weight of the gas mixture is approximately 30.6 g/mol30.6g/mol. Therefore, the closest option is: (c) 30.6