The density of an ideal gas can be doubled by halving the ______________.

Explanation:

Kinetic theory of gases-

• The kinetic theory of gases is a theoretical model that describes-
• the molecular composition of the gas in terms of a large number of identical tiny particles called molecules. 
• Further, this theory explains that gas pressure arises due to particles colliding with each other and the walls of the container.
• The kinetic theory of gases also defines thermodynamic variables such as temperature,
• viscosity, and thermal conductivity, and all these properties are related to the microscopic phenomenon.

An ideal gas is the one that can obey-

Ideal gas equation PV = nRT

Calculation:

Given:-

Pressure = P

Volume = V

Temperature = T

Mass = m

From ideal gas equation:-

PV = nRT

\(\Rightarrow P=\frac{n}{V}RT\)

\(\Rightarrow P=\frac{\rho }{M}RT\)

\(\Rightarrow P=\frac{\rho }{m}\times\frac{R}{N_{a}}\times T\) (where, M = mNa and R/Na = K = Boltzman constant)

\(\Rightarrow P=\frac{\rho KT}{m}\)

\(\therefore \rho =\frac{mP}{KT}\)

From the above, the density is inversly proportional to the temperature.

Therefore, The density of an ideal gas can be doubled by halving the Absolute temperature

Hence, option-3 is correct