A vessel of volume 5 litres contains `1.4 g` of `N_2` and `0.4 g` of He at `1500 K`. If `30 %` of the nitrogen molecules are dissociated into atoms then find the gas pressure.

Answer

A, B, D

Explanation

`n_1 = "number of moles of" N_2 = (1.4)/(28) = 0.05`
`30 %` of the gas dissociates into atoms.
`:. n_1 = 2 (0.3)(0.05) + (0.7)(0.05) = 0.065`
`n_2 =` number of moles of `"He" = (0.4)/(4) = 0.1`
`:. n = n_1' + n_2 = 0.165`
Now, `P = (n R T)/(V) = ((0.165)(8.31)(1500))/(5 xx 10^-3)`
= `4.1 xxx 10^5 N//m^2`.