168) An LPG cylinder contains 15 kg of butane gas at 27^oC and 10 atm pressure. It was leaking and its pressure fell down to 8 atm after 1 day. The gas leaked in 5 days is:

169) Oxygen gas is collected by downward displacement of water in a jar. The level of water inside the jar is adjusted to the height of water outside the jar. When the adjustment is made, the pressure exerted by oxygen is equal to:

170) The temperature at which the second virial coefficient of a real gas is zero is called:

171) The inversion temperature (T_i) for a gas is given by:

172) If for two gases of molecular weights M_A and M_B at temperature T_A and T_B , T_AM_B = T_BM_A, then which property has the same magnitude for both the gases?