Q: Air is filled at 60°C in a vessel of open mouth. The vessel is heated to a temperature T so that 1/4th part of air escapes. Assuming the volume of vessel remaining constant, the value of T is
(a) 80°C
(b) 444°C
(c) 333°C
(d) 171°C
Ans: (d)
Sol:
PV = nRT
PV =( m/M )RT
Open mouth means pressure is constant
Hence,
$ T \propto \frac{1}{m}$
$ \frac{T_1}{T_2} = \frac{m_2}{m_1} $
m2= 3m1/4
and , T1 = 60+273= 333K