Which of the following have identical bond order?

The molecules that will have dipole moment are

At 27^oC, hydrogen is leaked through a tiny hole into a vessel for 20 minutes. Another unknown gas at the same temperature and pressure as that of H₂ is leaked through the same hole for 20 minutes After the effusion of the gases the mixture exerts a pressure of 6 atmosphere. The hydrogen content of the mixture is 0.7 mole. If the volume of ther container is 3 litres, what is the molecular weight of the unknown gas?

At room temperature the following reacton is procedd nearly to completion:

2NO + O₂ $$\to$$ 2NO₂ $$\to$$ N₂O₄

The dimer, N₂O₄, solidifies at 262 K. A 250 ml flask and a 100 ml flask are separated by a stop-cock. At 300 K, the nitric oxide in the larger flask exerts a pressure of 1.053 atm. and the smaller one contains oxygen at 0.789 atm. The gases are mixed by the opening stopcock and after the end of raction the flasks are cooled at 220K. Neglecting the vapour pressure of the dimer, find out the pressure and composition of the gas remaining at 220 K. (Assume the gases to behave ideally)