Question

A box contains x molecules of a gas. How will the pressure of the gas be affected if the number of molecules is made 2x?

• A. Pressure will decrease.
• B. Pressure will remain unchanged.
• C. Pressure will be doubled.
• D. Pressure will become three times.

Answer 1

The correct option is C Pressure will be doubled.

we know that from ideal gas equation, PV = nRT
now, n = number of moles of gas = $\frac{N}{N_A}$, where N = number of molecules of the gas and $N_A$ is the Avogadro's number
So, putting the value of n in ideal gas equation, we get
$PV=\frac{N}{N_A}RT$
this means that pressure of the gas is proportional to the number of molecules of the gas at constant temperature and volume
So, if we double the number of molecules of the gas (2x), then pressure will also double
So, C is the correct answer.