Using ideal gas equation,
P\times V=n\times R\times T
Here,
P denotes pressure
V denotes volume
n denotes number of moles of gas
R denotes gas constant
T denotes temperature
The values at STP will be:
P=100 kPa
T=293 K
R=8.314472 L kPa K⁻¹ mol⁻¹
Number of moles of gas=3.43 mole
Putting all the values in the above equation,

V=83.55 L
So the volume will be 83.55 L.
83.55 L of radon gas would be in 3.43 moles at room temperature and pressure (293 K and 100 kPa).
Answer : Option A) Ethanoic Acid
Explanation : Ethanoic acid has the lowest vapor pressure i.e 0.08 atm at the temperature of 50°C compared to the other given options.
The vapour pressure of propanone at 50°C is 0.84 atm
Ethanol has vapour pressure as 0.30 atm at 50°C
water has vapour pressure of 0.12 atm at 50°C.
99.6 mg= .0996 g
.0996g x (1mol/125.05g) x (1 mol SO3/1 mol Na2SO2) x (6.02 x 10^22/1mol SO3) = 4.79 x 10^19 SO32- ions
Displacement = √(3² + 4²)
Displacement = 5 meters north east
Velocity = displacement / time
Velocity = 5 / 35
Velocity = 0.14 m/s northeast