A vessel contains two non-reactive gases neon (monoatomic) and oxygen (diatomic). The ratio of their partial pressures is 3:2. Estimate the ratio of
(i) number of molecules, and
(ii) mass density of neon and oxygen in the vessel.
Atomic mass of neon = 20.2 u, and molecular mass of oxygen = 32.0 u.

Options

A. `(2)/(3)`
B. `(3)/(2)`
C. `(4)/(3)`
D. `(3)/(4)`

Answer

B

Explanation

Each gas (assumed ideal ) obeys gas laws. Since ,Vand T are common to the two gases, we have
`p_(1)V=mu_(1)RT and p_(2)V=mu_(2)RT`
`(p_(1))/(p_(2))=(mu_(1))/(mu_(2))`
Here , 1 and 2 refer to neon and oxygen respectively.
`(P_(1))/(P_(2))=(3)/(2)`
Given `(mu_(1))/(mu_(2))=(3)/(2)`
By definition `mu_(1)=(N_(1))/(N_(A))`
and `mu_(2)=(N_(2))/(N_(A))`
Where , `N_(1)` and `N_(2)` are the number of molecules of 1 and 2 and `N_(A)` is Avogadro's number.
`(N_(1))/(N_(2))=(mu_(1))/(mu_(2))= (3)/(2)`