Correct Answer - B
Ideal gas equation can be written as
pV=nRT ….. (i)
In this equation ,
n= number of moles of the gas
p= pressure of the gas
V = volume of the gas
R= universal gas constant
and T = temperature of the gas
from Eq . (i) , We have , `(n)/(V)=(P)/(RT)="constant"`
So , at constant pressure and temperature , both balloons will contain equal number of molecules per unit volume.