the density of a gas at N.T.P is 1.40grams per litre. The molecular weight of gas is

To find the molecular weight of a gas, we need to know its density at a given temperature and pressure. In this case, the density of the gas is given as 1.40 grams per litre at N.T.P. (Normal Temperature and Pressure).

To find the molecular weight, we can use the ideal gas law equation, which states:

PV = nRT

Where:
- P is the pressure of the gas
- V is the volume of the gas
- n is the number of moles of the gas
- R is the ideal gas constant
- T is the temperature of the gas in Kelvin

At N.T.P., the pressure is 1 atmosphere (1 atm) and the temperature is 273.15 Kelvin (0 degrees Celsius).

Now, let's calculate the molar volume of the gas at N.T.P:

1 mole of any ideal gas occupies 22.4 liters at N.T.P (per Avogadro's law). Therefore, if the density is 1.40 grams per litre, then the molar mass of the gas is:

1.40 grams/litre * 22.4 litres/mole = 31.36 grams/mole.

So, the molecular weight of the gas is approximately 31.36 grams per mole.

Answer

31.36

PV=nRT

n/V=P /RT n/V; but n=mass/molmass*volume, so density/molmass=n/V

n/V=density/molmass then
molmass=density*RT/Pressure

put in NTP, and you have it.